Inline the call to SynthOnTimer.

src/libespeak-ng/speech.c

 #include <ctype.h>
 #include <errno.h>
 #include <locale.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 	SpeakNextClause(NULL, text, 0);
 
 	if (my_mode == (ENOUTPUT_MODE_SYNCHRONOUS | ENOUTPUT_MODE_SPEAK_AUDIO)) {
-		for (;;) {
+		bool continue_speaking = true;
+		while (continue_speaking) {
 #ifdef PLATFORM_WINDOWS
 			Sleep(300); // 0.3s
 #else
 			sleep(1);
 #endif
 #endif
-			if (SynthOnTimer() != 0)
-				break;
+			do {
+				if (WcmdqUsed() > 0)
+					WavegenOpenSound();
+
+				if (Generate(phoneme_list, &n_phoneme_list, 1) == 0) {
+					if (SpeakNextClause(NULL, NULL, 1) == 0)
+						continue_speaking = WavegenCloseSound() == 0;
+				}
+			} while (skipping_text);
 		}
 		return ENS_OK;
 	}

src/libespeak-ng/synthesize.c

 	return 0; // finished the phoneme list
 }
 
-int SynthOnTimer()
-{
-	do {
-		if (WcmdqUsed() > 0)
-			WavegenOpenSound();
-
-		if (Generate(phoneme_list, &n_phoneme_list, 1) == 0) {
-			if (SpeakNextClause(NULL, NULL, 1) == 0)
-				return WavegenCloseSound();
-		}
-	} while (skipping_text);
-
-	return 0;
-}
-
 int SpeakNextClause(FILE *f_in, const void *text_in, int control)
 {
 	// Speak text from file (f_in) or memory (text_in)

src/libespeak-ng/synthesize.h

 void SynthesizeInit(void);
 int  Generate(PHONEME_LIST *phoneme_list, int *n_ph, int resume);
 void MakeWave2(PHONEME_LIST *p, int n_ph);
-int  SynthOnTimer(void);
 int  SpeakNextClause(FILE *f_text, const void *text_in, int control);
 void SetSpeed(int control);
 void SetEmbedded(int control, int value);