diff --git a/README b/README
index 8d1732e9..77beb2a6 100644
--- a/README
+++ b/README
@@ -20,7 +20,7 @@ Carsten Wollesen for donating Telefunken 4015 B-Netz phone back in the 90's.
 Klaus Adler for helping me to retrieve complete NMT specification and donating
 a BSA44 (magnetic card C-Netz hackable phone) back in the 90's.
 
-Andy Zauner for providing signalling specification of C-Netz back in the 90's.
+Andy Zauner for providing signaling specification of C-Netz back in the 90's.
 
 Hans Wigger for providing valuable informations about A-Netz and B-Netz and
 helping me to get an A-Netz phone.
diff --git a/src/amps/amps.c b/src/amps/amps.c
index aab19324..f3648b58 100644
--- a/src/amps/amps.c
+++ b/src/amps/amps.c
@@ -510,21 +510,21 @@ static void amps_release(transaction_t *trans, uint8_t cause)
 }
 
 /*
- * receive signalling
+ * receive signaling
  */
 
-void amps_rx_signalling_tone(amps_t *amps, int tone, double quality)
+void amps_rx_signaling_tone(amps_t *amps, int tone, double quality)
 {
 	transaction_t *trans = amps->trans_list;
 	if (trans == NULL) {
-		PDEBUG(DAMPS, DEBUG_ERROR, "Signalling Tone without transaction, please fix!\n");
+		PDEBUG(DAMPS, DEBUG_ERROR, "Signaling Tone without transaction, please fix!\n");
 		return;
 	}
 	
 	if (tone)
-		PDEBUG(DAMPS, DEBUG_INFO, "Detected Signalling Tone with quality=%.0f.\n", quality * 100.0);
+		PDEBUG(DAMPS, DEBUG_INFO, "Detected Signaling Tone with quality=%.0f.\n", quality * 100.0);
 	else
-		PDEBUG(DAMPS, DEBUG_INFO, "Lost Signalling Tone signal\n");
+		PDEBUG(DAMPS, DEBUG_INFO, "Lost Signaling Tone signal\n");
 
 	switch (trans->state) {
 	case TRANS_CALL:
@@ -559,7 +559,7 @@ void amps_rx_signalling_tone(amps_t *amps, int tone, double quality)
 		}
 		break;
 	default:
-		PDEBUG(DAMPS, DEBUG_ERROR, "Signalling Tone without active call, please fix!\n");
+		PDEBUG(DAMPS, DEBUG_ERROR, "Signaling Tone without active call, please fix!\n");
 	}
 }
 
@@ -625,7 +625,7 @@ void amps_rx_recc(amps_t *amps, uint8_t scm, uint32_t esn, uint32_t min1, uint16
 	transaction_t *trans;
 	const char *callerid = amps_min2number(min1, min2);
 
-	/* check if we are busy, so we ignore all signalling */
+	/* check if we are busy, so we ignore all signaling */
 	if (amps->state == STATE_BUSY) {
 		PDEBUG(DAMPS, DEBUG_NOTICE, "Ignoring RECC messages from phone while using this channel for voice.\n");
 		return;
diff --git a/src/amps/amps.h b/src/amps/amps.h
index 1ce3c625..ec804fe0 100644
--- a/src/amps/amps.h
+++ b/src/amps/amps.h
@@ -160,7 +160,7 @@ const char *amps_min2number(uint32_t min1, uint16_t min2);
 const char *amps_scm(uint8_t scm);
 int amps_create(int channel, enum amps_chan_type chan_type, const char *sounddev, int samplerate, int cross_channels, double rx_gain, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, amps_si *si, uint16_t sid, uint8_t sat, int polarity, int loopback);
 void amps_destroy(sender_t *sender);
-void amps_rx_signalling_tone(amps_t *amps, int tone, double quality);
+void amps_rx_signaling_tone(amps_t *amps, int tone, double quality);
 void amps_rx_sat(amps_t *amps, int tone, double quality);
 void amps_rx_recc(amps_t *amps, uint8_t scm, uint32_t esn, uint32_t min1, uint16_t min2, uint8_t msg_type, uint8_t ordq, uint8_t order, const char *dialing);
 transaction_t *amps_tx_frame_focc(amps_t *amps);
diff --git a/src/amps/dsp.c b/src/amps/dsp.c
index 8847c72f..7668ff2f 100644
--- a/src/amps/dsp.c
+++ b/src/amps/dsp.c
@@ -78,14 +78,14 @@
 #define COMPANDOR_0DB		45000	/* works quite well */
 #define BITRATE			10000
 #define SIG_TONE_CROSSINGS	2000	/* 2000 crossings are 100ms @ 10 KHz */
-#define SIG_TONE_MINBITS	950	/* minimum bit durations to detect signalling tone (1000 is perfect for 100 ms) */
+#define SIG_TONE_MINBITS	950	/* minimum bit durations to detect signaling tone (1000 is perfect for 100 ms) */
 #define SIG_TONE_MAXBITS	1050	/* as above, maximum bits */
 #define SAT_DURATION		0.100	/* duration of SAT signal measurement */
 #define SAT_QUALITY		0.85	/* quality needed to detect sat */
 #define SAT_DETECT_COUNT	3	/* number of measures to detect SAT signal (specs say 250ms) */
 #define SAT_LOST_COUNT		3	/* number of measures to loose SAT signal (specs say 250ms) */
-#define SIG_DETECT_COUNT	3	/* number of measures to detect Signalling Tone */
-#define SIG_LOST_COUNT		2	/* number of measures to loose Signalling Tone */
+#define SIG_DETECT_COUNT	3	/* number of measures to detect Signaling Tone */
+#define SIG_LOST_COUNT		2	/* number of measures to loose Signaling Tone */
 #define CUT_OFF_HIGHPASS	300.0   /* cut off frequency for high pass filter to remove dc level from sound card / sample */
 #define BEST_QUALITY		0.68	/* Best possible RX quality */
 
@@ -96,7 +96,7 @@ static double sat_freq[5] = {
 	6000.0,
 	6030.0,
 	5800.0, /* noise level to check against */
-	10000.0, /* signalling tone */
+	10000.0, /* signaling tone */
 };
 
 static int dsp_sine_sat[256];
@@ -652,7 +652,7 @@ void sender_receive_frame(amps_t *amps, int16_t *samples, int length)
 }
 
 
-/* decode signalling tone */
+/* decode signaling tone */
 /* compare supervisory signal against noise floor on 5800 Hz */
 static void sat_decode(amps_t *amps, int16_t *samples, int length)
 {
@@ -661,7 +661,7 @@ static void sat_decode(amps_t *amps, int16_t *samples, int length)
 
 	coeff[0] = amps->sat_coeff[amps->sat];
 	coeff[1] = amps->sat_coeff[3]; /* noise floor detection */
-	coeff[2] = amps->sat_coeff[4]; /* signalling tone */
+	coeff[2] = amps->sat_coeff[4]; /* signaling tone */
 	audio_goertzel(samples, length, 0, coeff, result, 3);
 
 	quality[0] = (result[0] - result[1]) / result[0];
@@ -673,7 +673,7 @@ static void sat_decode(amps_t *amps, int16_t *samples, int length)
 
 	PDEBUG(DDSP, DEBUG_NOTICE, "SAT level %.2f%% quality %.0f%%\n", result[0] * 32767.0 / SAT_DEVIATION / 0.63662 * 100.0, quality[0] * 100.0);
 	if (amps->sender.loopback || debuglevel == DEBUG_DEBUG) {
-		PDEBUG(DDSP, debuglevel, "Signalling Tone level %.2f%% quality %.0f%%\n", result[2] * 32767.0 / FSK_DEVIATION / 0.63662 * 100.0, quality[1] * 100.0);
+		PDEBUG(DDSP, debuglevel, "Signaling Tone level %.2f%% quality %.0f%%\n", result[2] * 32767.0 / FSK_DEVIATION / 0.63662 * 100.0, quality[1] * 100.0);
 	}
 	if (quality[0] > SAT_QUALITY) {
 		if (amps->sat_detected == 0) {
@@ -704,8 +704,8 @@ static void sat_decode(amps_t *amps, int16_t *samples, int length)
 			if (amps->sig_detect_count == SIG_DETECT_COUNT) {
 				amps->sig_detected = 1;
 				amps->sig_detect_count = 0;
-				PDEBUG(DDSP, DEBUG_DEBUG, "Signalling Tone detected with level=%.0f%%, quality=%.0f%%.\n", result[2] / 0.63662 * 100.0, quality[1] * 100.0);
-				amps_rx_signalling_tone(amps, 1, quality[1]);
+				PDEBUG(DDSP, DEBUG_DEBUG, "Signaling Tone detected with level=%.0f%%, quality=%.0f%%.\n", result[2] / 0.63662 * 100.0, quality[1] * 100.0);
+				amps_rx_signaling_tone(amps, 1, quality[1]);
 			}
 		} else
 			amps->sig_detect_count = 0;
@@ -715,15 +715,15 @@ static void sat_decode(amps_t *amps, int16_t *samples, int length)
 			if (amps->sig_detect_count == SIG_LOST_COUNT) {
 				amps->sig_detected = 0;
 				amps->sig_detect_count = 0;
-				PDEBUG(DDSP, DEBUG_DEBUG, "Signalling Tone lost.\n");
-				amps_rx_signalling_tone(amps, 0, 0.0);
+				PDEBUG(DDSP, DEBUG_DEBUG, "Signaling Tone lost.\n");
+				amps_rx_signaling_tone(amps, 0, 0.0);
 			}
 		} else
 			amps->sig_detect_count = 0;
 	}
 }
 
-/* decode signalling/audio */
+/* decode signaling/audio */
 /* Count SIG_TONE_CROSSINGS of zero crossings, then check if the elapsed bit
  * time is between SIG_TONE_MINBITS and SIG_TONE_MAXBITS. If it is, the
  * frequency is close to the singalling tone, so it is detected
diff --git a/src/amps/main.c b/src/amps/main.c
index 0d787034..27c7b291 100644
--- a/src/amps/main.c
+++ b/src/amps/main.c
@@ -322,7 +322,7 @@ int main(int argc, char *argv[])
 		fprintf(stderr, "*******************************************************************************\n");
 		fprintf(stderr, "I strongly suggest to let me do pre- and de-emphasis (options -E -e)!\n");
 		fprintf(stderr, "Use a transmitter/receiver without emphasis and let me do that!\n");
-		fprintf(stderr, "Because carrier FSK signalling does not use emphasis, I like to control\n");
+		fprintf(stderr, "Because carrier FSK signaling does not use emphasis, I like to control\n");
 		fprintf(stderr, "emphasis by myself for best results.\n");
 		fprintf(stderr, "*******************************************************************************\n");
 	}
diff --git a/src/amps/transaction.h b/src/amps/transaction.h
index 760207ea..cc062b30 100644
--- a/src/amps/transaction.h
+++ b/src/amps/transaction.h
@@ -9,8 +9,8 @@ enum amps_trans_state {
 	TRANS_CALL_MO_ASSIGN_SEND,	/* assigning channel, sending assignment */
 	TRANS_CALL_MT_ASSIGN,		/* assigning channel, waiting to send */
 	TRANS_CALL_MT_ASSIGN_SEND,	/* assigning channel, sending assignment */
-	TRANS_CALL_MT_ALERT,		/* ringing the phone, sending alert order until signalling tone is received */
-	TRANS_CALL_MT_ALERT_SEND,	/* ringing the phone, signalling tone is received */
+	TRANS_CALL_MT_ALERT,		/* ringing the phone, sending alert order until signaling tone is received */
+	TRANS_CALL_MT_ALERT_SEND,	/* ringing the phone, signaling tone is received */
 	TRANS_CALL_REJECT,		/* rejecting channel, waiting to send */
 	TRANS_CALL_REJECT_SEND,		/* rejecting channel, sending reject */
 	TRANS_CALL,			/* active call */
diff --git a/src/anetz/dsp.c b/src/anetz/dsp.c
index aed2334c..60d4118d 100644
--- a/src/anetz/dsp.c
+++ b/src/anetz/dsp.c
@@ -32,8 +32,8 @@
 
 #define PI		3.1415927
 
-/* signalling */
-/* NOTE: The peak deviation is similar for paging tone and signalling tone,
+/* signaling */
+/* NOTE: The peak deviation is similar for paging tone and signaling tone,
  * so both tones should be equal after pre-emphasis. This is why the paging
  * tones is so much louder.*/
 #define TX_PEAK_TONE	8192.0	/* peak amplitude for all tones */
@@ -50,7 +50,7 @@
 
 extern int page_sequence;
 
-/* two signalling tones */
+/* two signaling tones */
 static double fsk_tones[2] = {
 	2280.0,
 	1750.0,
diff --git a/src/bnetz/dsp.c b/src/bnetz/dsp.c
index 375abca4..e86af6d9 100644
--- a/src/bnetz/dsp.c
+++ b/src/bnetz/dsp.c
@@ -32,7 +32,7 @@
 
 #define PI		3.1415927
 
-/* signalling */
+/* signaling */
 #define TX_PEAK_TONE	5000.0	/* peak amplitude for all tones */
 #define BIT_DURATION	0.010	/* bit length: 10 ms */
 #define FILTER_STEP	0.001	/* step every 1 ms */
@@ -44,7 +44,7 @@
 #define LOSS_INTERVAL	1000	/* filter steps (milliseconds) for one second interval */
 #define LOSS_TIME	12	/* duration of signal loss before release */
 
-/* two signalling tones */
+/* two signaling tones */
 static double fsk_bits[2] = {
 	2070.0,
 	1950.0,
diff --git a/src/cnetz/cnetz.c b/src/cnetz/cnetz.c
index b9c1ea50..b5e90f8b 100644
--- a/src/cnetz/cnetz.c
+++ b/src/cnetz/cnetz.c
@@ -757,12 +757,12 @@ const telegramm_t *cnetz_transmit_telegramm_rufblock(cnetz_t *cnetz)
 		telegramm.futln_rest_nr = trans->futln_rest;
 		switch (trans->state) {
 		case TRANS_EM:
-			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgement 'Einbuchquittung' to Attachment request.\n");
+			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgment 'Einbuchquittung' to Attachment request.\n");
 			telegramm.opcode = OPCODE_EBQ_R;
 			destroy_transaction(trans);
 			break;
 		case TRANS_UM:
-			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgement 'Umbuchquittung' to Roaming requuest.\n");
+			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgment 'Umbuchquittung' to Roaming requuest.\n");
 			telegramm.opcode = OPCODE_UBQ_R;
 			destroy_transaction(trans);
 			break;
@@ -851,7 +851,7 @@ const telegramm_t *cnetz_transmit_telegramm_meldeblock(cnetz_t *cnetz)
 	if (trans) {
 		switch (trans->state) {
 		case TRANS_VWG:
-			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgement 'Wahlaufforderung' to outging call\n");
+			PDEBUG(DCNETZ, DEBUG_INFO, "Sending acknowledgment 'Wahlaufforderung' to outging call\n");
 			telegramm.opcode = OPCODE_WAF_M;
 			telegramm.futln_nationalitaet = trans->futln_nat;
 			telegramm.futln_heimat_fuvst_nr = trans->futln_fuvst;
diff --git a/src/cnetz/cnetz.h b/src/cnetz/cnetz.h
index bbdd9377..b158e91d 100644
--- a/src/cnetz/cnetz.h
+++ b/src/cnetz/cnetz.h
@@ -30,12 +30,12 @@ enum cnetz_state {
 
 /* timers */
 #define F_BQ		8		/* number of not received frames at BQ state */
-#define F_VHQK		16		/* number of not received frames at VHQ state during concentrated signalling */
-#define F_VHQ		16		/* number of not received frames at VHQ state during distributed signalling */
+#define F_VHQK		16		/* number of not received frames at VHQ state during concentrated signaling */
+#define F_VHQ		16		/* number of not received frames at VHQ state during distributed signaling */
 #define F_DS		16		/* number of not received frames at DS state */
 #define F_RTA		16		/* number of not received frames at RTA state */
-#define N_AFKT		6		/* number of release frames to send during concentrated signalling */
-#define N_AFV		4		/* number of release frames to send during distributed signalling */
+#define N_AFKT		6		/* number of release frames to send during concentrated signaling */
+#define N_AFV		4		/* number of release frames to send during distributed signaling */
 
 /* clear causes */
 #define CNETZ_CAUSE_TEILNEHMERBESETZT	0	/* subscriber busy */
diff --git a/src/cnetz/fsk_fm_demod.c b/src/cnetz/fsk_fm_demod.c
index e678ca39..50d5fcde 100644
--- a/src/cnetz/fsk_fm_demod.c
+++ b/src/cnetz/fsk_fm_demod.c
@@ -38,7 +38,7 @@
  *
  * To determine a change from noise, we use a theshold. This is set to half of
  * the level of last received change. This means that the next change may be
- * down to a half lower.  There is a special case during distributed signalling.
+ * down to a half lower.  There is a special case during distributed signaling.
  * The first level change of each data chunk raises or falls from 0-level
  * (unmodulated carrier), so the threshold for this bit is only a quarter of the
  * last received change.
@@ -418,7 +418,7 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, int16_t *samples, int length)
 	bit_time_uncorrected = fsk->bit_time_uncorrected;
 	bit_count = fsk->bit_count;
 
-	/* process signalling block, sample by sample */
+	/* process signaling block, sample by sample */
 	for (i = 0; i < length; i++) {
 		spl[pos++] = samples[i];
 		if (pos == len)
@@ -431,7 +431,7 @@ void fsk_fm_demod(fsk_fm_demod_t *fsk, int16_t *samples, int length)
 #endif
 			find_change(fsk);
 		} else {
-			/* in distributed signalling, measure over 5 bits, but ignore 5th bit.
+			/* in distributed signaling, measure over 5 bits, but ignore 5th bit.
 			 * also reset next_bit, as soon as we reach the window */
 
 			/* note that we start from 0.5, because we detect change 0.5 bits later,
diff --git a/src/cnetz/fsk_fm_demod.h b/src/cnetz/fsk_fm_demod.h
index dc224bed..abc86634 100644
--- a/src/cnetz/fsk_fm_demod.h
+++ b/src/cnetz/fsk_fm_demod.h
@@ -27,7 +27,7 @@ typedef struct fsk_fm_demod {
 	int		level_threshold;	/* threshold for detection of next level change */
 	double		bits_per_sample;	/* duration of one sample in bits */
 	double		next_bit;		/* count time to detect bits */
-	int		bit_count;		/* counts bits, to match 4 bits at distributed signalling */
+	int		bit_count;		/* counts bits, to match 4 bits at distributed signaling */
 	int		last_change_positive;	/* flags last level change direction */
 	enum fsk_sync	sync;			/* set, if we are in sync and what polarity we receive */
 	double		sync_level;		/* what was the level, when we received the sync */
diff --git a/src/cnetz/main.c b/src/cnetz/main.c
index 2cc9c54c..21e7574c 100644
--- a/src/cnetz/main.c
+++ b/src/cnetz/main.c
@@ -276,7 +276,7 @@ int main(int argc, char *argv[])
 		fprintf(stderr, "*******************************************************************************\n");
 		fprintf(stderr, "I strongly suggest to let me do pre- and de-emphasis (options -E -e)!\n");
 		fprintf(stderr, "Use a transmitter/receiver without emphasis and let me do that!\n");
-		fprintf(stderr, "Because carrier FSK signalling and scrambled voice (default) does not use\n");
+		fprintf(stderr, "Because carrier FSK signaling and scrambled voice (default) does not use\n");
 		fprintf(stderr, "emphasis, I like to control emphasis by myself for best results.\n");
 		fprintf(stderr, "*******************************************************************************\n");
 	}
diff --git a/src/cnetz/telegramm.c b/src/cnetz/telegramm.c
index 5281089f..75ed2ea0 100644
--- a/src/cnetz/telegramm.c
+++ b/src/cnetz/telegramm.c
@@ -1522,7 +1522,7 @@ selected:
 	switch (cnetz->dsp_mode) {
 	case DSP_MODE_OGK:
 		if (definition_opcode[opcode].block != BLOCK_R && definition_opcode[opcode].block != BLOCK_M) {
-			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used OgK channel signalling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
+			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used OgK channel signaling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
 			return;
 		}
 		/* determine block by last timeslot sent and by message type */
@@ -1533,14 +1533,14 @@ selected:
 		break;
 	case DSP_MODE_SPK_K:
 		if (definition_opcode[opcode].block != BLOCK_K) {
-			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used for concentrated signalling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
+			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used for concentrated signaling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
 			return;
 		}
 		cnetz_receive_telegramm_spk_k(cnetz, &telegramm);
 		break;
 	case DSP_MODE_SPK_V:
 		if (definition_opcode[opcode].block != BLOCK_V) {
-			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used for distributed signalling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
+			PDEBUG(DFRAME, DEBUG_NOTICE, "Received Telegramm that is not used for distributed signaling, ignoring! (opcode %d = %s)\n", opcode, definition_opcode[opcode].message_name);
 			return;
 		}
 		cnetz_receive_telegramm_spk_v(cnetz, &telegramm);
diff --git a/src/common/mncc.h b/src/common/mncc.h
index e0c7afa2..32d906f7 100644
--- a/src/common/mncc.h
+++ b/src/common/mncc.h
@@ -124,7 +124,7 @@ enum gsm48_bcap_ra {
 	GSM48_BCAP_RA_OTHER	= 3,
 };
 
-/* GSM 04.08 Bearer Capability: Signalling access protocol */
+/* GSM 04.08 Bearer Capability: Signaling access protocol */
 enum gsm48_bcap_sig_access {
 	GSM48_BCAP_SA_I440_I450	= 1,
 	GSM48_BCAP_SA_X21	= 2,
diff --git a/src/nmt/dsp.c b/src/nmt/dsp.c
index 4badbc92..df548947 100644
--- a/src/nmt/dsp.c
+++ b/src/nmt/dsp.c
@@ -31,9 +31,9 @@
 
 #define PI			M_PI
 
-/* signalling */
+/* signaling */
 #define COMPANDOR_0DB		32767	/* works quite well */
-#define TX_PEAK_FSK		10000.0	/* peak amplitude of signalling FSK */
+#define TX_PEAK_FSK		10000.0	/* peak amplitude of signaling FSK */
 #define TX_PEAK_SUPER		1000.0	/* peak amplitude of supervisory signal */
 #define BIT_RATE		1200	/* baud rate */
 #define STEPS_PER_BIT		10	/* step every 1/12000 sec */
@@ -43,7 +43,7 @@
 #define SUPER_DETECT_COUNT	4	/* number of measures to detect supervisory signal */
 #define MUTE_DURATION		0.280	/* a tiny bit more than two frames */
 
-/* two signalling tones */
+/* two signaling tones */
 static double fsk_bits[2] = {
 	1800.0,
 	1200.0,
diff --git a/src/nmt/frame.c b/src/nmt/frame.c
index e09b2a4d..7125e72e 100644
--- a/src/nmt/frame.c
+++ b/src/nmt/frame.c
@@ -215,14 +215,14 @@ static struct nmt_frame {
 	{ NMT_MESSAGE_6,	"JJJPJJJJJJJJJJJJ", MTX_TO_XX, 0,	"6",	"Idle frame" },
 	{ NMT_MESSAGE_7,	"NNNPYYCCCCCCCJJJ", MTX_TO_MS, 8,	"7",	"Authentication request" },
 	{ NMT_MESSAGE_8,	"NNNPYYMHHHHHHHWW", MTX_TO_MS, 1,	"8",	"A-subscriber number" },
-	{ NMT_MESSAGE_10a,	"NNNPZXXXXXXTJJJJ", MS_TO_MTX, 1,	"10a",	"Call acknowledgement from MS on calling channel (shortened frame)" },
+	{ NMT_MESSAGE_10a,	"NNNPZXXXXXXTJJJJ", MS_TO_MTX, 1,	"10a",	"Call acknowledgment from MS on calling channel (shortened frame)" },
 	{ NMT_MESSAGE_10b,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 1,	"10b",	"Seizure from ordinary MS and identity on traffic channel" },
 	{ NMT_MESSAGE_10c,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 6,	"10c",	"Seizure and identity from called MS on traffic channel" },
 	{ NMT_MESSAGE_11a,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 14,	"11a",	"Roaming updating seizure and identity on traffic channel" },
-	{ NMT_MESSAGE_11b,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 15,	"11b",	"Seizure and call achnowledgement on calling channel from MS with priority (shortened frame)" },
+	{ NMT_MESSAGE_11b,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 15,	"11b",	"Seizure and call achnowledgment on calling channel from MS with priority (shortened frame)" },
 	{ NMT_MESSAGE_12,	"NNNPZXXXXXXTYKKK", MS_TO_MTX, 11,	"12",	"Seizure from coin-box on traffic channel" },
 	{ NMT_MESSAGE_13a,	"NNNPZXXXXXXLLLLL", MS_TO_MTX, 8,	"13a",	"Line signal" },
-	{ NMT_MESSAGE_13b,	"NNNPZXXXXXXLLLQQ", MS_TO_MTX, 8,	"13b",	"Line signal: Answer acknowledgement from coin box" },
+	{ NMT_MESSAGE_13b,	"NNNPZXXXXXXLLLQQ", MS_TO_MTX, 8,	"13b",	"Line signal: Answer acknowledgment from coin box" },
 	{ NMT_MESSAGE_14a,	"NNNPZXXXXXXSSSSS", MS_TO_MTX, 7,	"14a",	"Digit signal (1st, 3rd, 5th ........digit)" },
 	{ NMT_MESSAGE_14b,	"NNNPZXXXXXXSSSSS", MS_TO_MTX, 7,	"14b",	"Digit signal (2nd, 4th, 6th ........digit)" },
 	{ NMT_MESSAGE_15,	"JJJPJJJJJJJJJJJJ", XX_TO_MTX, 0,	"15",	"Idle frame" },
@@ -383,7 +383,7 @@ static const char *param_line_signal(uint64_t value, int ndigits, enum nmt_direc
 			desc = "Clearing, release guard";
 			break;
 		case 2:
-			desc = "Answer acknowledgement, (coin-box)";
+			desc = "Answer acknowledgment, (coin-box)";
 			break;
 		case 5:
 			desc = "Register recall ";
diff --git a/src/nmt/nmt.c b/src/nmt/nmt.c
index 5bb31635..ec56c497 100644
--- a/src/nmt/nmt.c
+++ b/src/nmt/nmt.c
@@ -963,12 +963,12 @@ static void tx_mt_paging(nmt_t *nmt, frame_t *frame)
 static void rx_mt_paging(nmt_t *nmt, frame_t *frame)
 {
 	switch (frame->mt) {
-	case NMT_MESSAGE_10a: /* call acknowledgement */
+	case NMT_MESSAGE_10a: /* call acknowledgment */
 		if (!match_channel(nmt, frame))
 			break;
 		if (!match_subscriber(nmt, frame))
 			break;
-		PDEBUG(DNMT, DEBUG_INFO, "Received call acknowledgement on channel %d.\n", nmt->sender.kanal);
+		PDEBUG(DNMT, DEBUG_INFO, "Received call acknowledgment on channel %d.\n", nmt->sender.kanal);
 		nmt_new_state(nmt, STATE_MT_CHANNEL);
 		nmt->tx_frame_count = 0;
 		if (nmt->page_for_nmt) {