Improve vowel sound for Latvian

espeak-ng-data/lang/bat/lv

 pitch 64 118
 breath   10 2 1 0 0 0 0 0
 breathw  20 42 85 200 500 1000
-tone 60 80 450 255 750 10 3000 255
+tone 60 150 204 100 400 255 700 10 3000 255
 stressAmp 12 10 8 8 0 0 15 16
 stressLength 160 140 200 140 0 0 240 160

phsource/ph_latvian

   vwl starttype #a endtype #i
   length 280
   lng
-  FMT(vdiph/aai, 100)
+  FMT(vwl_lv/ai, 100)
 endphoneme
 
 phoneme au
   vwl starttype #a endtype #u
   length 280
   lng
-  FMT(vdiph/aau, 100)
+  FMT(vwl_lv/au, 100)
 endphoneme
 
 phoneme ei
   vwl starttype #e endtype #i
   length 280
   lng
-  FMT(vdiph/eei_2, 100)
+  FMT(vwl_lv/ei, 100)
 endphoneme
 
 phoneme ie
   vwl starttype #i endtype #e
   length 250
   lng
-  FMT(vdiph2/ie_2, 100)
+  FMT(vwl_lv/ie, 100)
 endphoneme
 
 phoneme iu
   vwl starttype #i endtype #u
   length 250
   lng
-  FMT(vdiph2/iu_2, 100)
+  FMT(vwl_lv/iu, 100)
 endphoneme
 
 phoneme ui
   vwl starttype #u endtype #i
   length 250
   lng
-  FMT(vdiph/ui, 100)
+  FMT(vwl_lv/ui, 100)
 endphoneme
 
 phoneme uo
   vwl starttype #u endtype #a
   length 280
   lng
-  FMT(vdiph2/ua, 110)
+  FMT(vwl_lv/ua, 110)
 endphoneme
 
 phoneme uo`     // shorter version of uo
   ipa uo
   length 150
   lng
-  FMT(vdiph2/ua, 90)
+  FMT(vwl_lv/ua, 90)
 endphoneme
 
 phoneme oi
   vwl starttype #o endtype #i
   length 250
   lng
-  FMT(vdiph/ooi, 100)
+  FMT(vwl_lv/oi, 100)
 endphoneme
 
 phoneme ts

tests/language-phonemes.test

 test_lang la 080bd53c20991eae7baec73b8c735eacc8aae076 "ma na Na pa p<h>a ba ta t<h>a da ka k<h>a ga fa sa za ha Ra la ja wa _:_ ma mE mI mO mU ma: me: mi: mo: mu: my my: maU maI meI mEU mOI"
 test_lang lfn 044e27a5100528760a185e0773dccaca504b5bd4 "ma na Na pa ba ta da ka ga fa va sa za Sa Za ha la ja R2a **a wa _:_ ma me mi mo mu maI maU meU moI"
 test_lang lt 615e503b996ea5f7b267ebd77b91e77c5b874e18 "ma m;a na n;a pa p;a ta t;a ka k;a ba b;a da d;a ga g;a tsa ts;a tSa tS;a dza dz;a dZa dZ;a fa f;a sa s;a Sa S;a xa x;a va v;a za z;a Za Z;a la l;a ra r;a ja _:_ m@ ma mA ma: me mE me: mee meA mi mI mi: mo mO mo: mu mU mu: mw mW mai mei mau muo moi mui mie maU meU moU maI meI"
-test_lang lv b20e6cc99cd96551294060eecd7d199f9fe446ae "ma na n^a Na pa ba ta da ca Ja ka ga tsa dza Dz\`a tSa dZa DZ\`a fa va sa za Sa Za xa ha ja la l^a Ra ra _:_ mi my mu mE me mo ma mi: my: mu: mE: me: mo: ma: mai mau mei mie miu mui muo muo\` moi"
+test_lang lv fd8368720b9ea3e63a99c3e86580b8d74bf85882 "ma na n^a Na pa ba ta da ca Ja ka ga tsa dza Dz\`a tSa dZa DZ\`a fa va sa za Sa Za xa ha ja la l^a Ra ra _:_ mi my mu mE me mo ma mi: my: mu: mE: me: mo: ma: mai mau mei mie miu mui muo muo\` moi"
 test_lang mi b6e622de46c33181cdfea351b907f932da9a0a1a "ma na Na pa ta ka fa ha ra wa _:_ ma ma: me me: mi mi: mo mo: mu mu:"
 test_lang mk 072d0a74acf54bea528e7dde427eb04808d38364 "ma na n^a Na pa ta xa k^a ka ba da Ja ga tsa tSa tS;a dza dZa dZ;a fa sa Sa xa va za Za l^a la ja Ra @-*a ra _:_ ma me mi mo mu mA mE ma: me: mi: mo: mu: moU"
 test_lang shn e568aca66c2f58fdaf5dda8a67f4d21f05710234 "ma na Ja Na pa p_ha ba ta t_ha da ka k_ha ga ?a fa sa za Ta ha tS;a Ra ja wa la _:_ mi mI mW mu me m@ mo mE ma ma: mO miu meu mEu mau ma:u mWi mui m@i moi mai ma:i mOi maW _:_ ma1 ma2 ma3 ma4 ma5 ma6"