Use the place of articulation constants to specify the place-based conditions.

src/libespeak-ng/compiledata.c

 	{ "isFlag1",    0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_FLAG1 },
 	{ "isFlag2",    0, CONDITION_IS_PHFLAG_SET | phFLAGBIT_FLAG2 },
 
-	{ "isVel", 0, i_isVel },
+	{ "isVel", 0, CONDITION_IS_PLACE_OF_ARTICULATION | phPLACE_VELAR },
 
 	{ "isDiminished",  0, i_isDiminished },
 	{ "isUnstressed",  0, i_isUnstressed },

src/libespeak-ng/synthdata.c

 		switch (instn & 0xe0)
 		{
 		case CONDITION_IS_PHONEME_TYPE:
-			// phoneme type, vowel, nasal, fricative, etc
 			return ph->type == data;
-		case 0x20:
-			// place of articulation
+		case CONDITION_IS_PLACE_OF_ARTICULATION:
 			return ((ph->phflags >> 16) & 0xf) == data;
 		case CONDITION_IS_PHFLAG_SET:
-			// is a bit set in phoneme flags
 			return (ph->phflags & (1 << data)) != 0;
 		case 0x80:
 			switch (data)

src/libespeak-ng/synthesize.h

 /*
  * Copyright (C) 2005 to 2014 by Jonathan Duddington
  * email: [email protected]
- * Copyright (C) 2015-2016 Reece H. Dunn
+ * Copyright (C) 2015-2017 Reece H. Dunn
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
 #define i_isSecondVowel 0x8e
 #define i_IsTranslationGiven 0x90
 
-// place of articulation
-#define i_isVel      0x28
-
 #define CONDITION_IS_PHONEME_TYPE 0x00
+#define CONDITION_IS_PLACE_OF_ARTICULATION 0x20
 #define CONDITION_IS_PHFLAG_SET 0x40
 
 #define i_StressLevel  0x800