Syntax and prosody in a Danish Text-to-Speech
System
Peter Molbcek Hansen & Ebbe Spang-Hanssen
University o f Copenhagen
0, Introduction
T h is p a p e r is stru c tu re d as fo llo w s:
In se ctio n 1. w e p re s e n t th e b a s ic stru c tu re o f a D a n ish te x t-to -s p e e c h sy ste m (h e n c e fo rth T T S -sy s- tem ), an d illu strate so m e o f th e sp ecial n e e d s o f T T S -s y s te m s a s c o m p a re d w ith o th e r n a tu ra l la n g u a g e p ro c e ssin g sy ste m s (N L P -sy ste m s). In th is c o n n e c tio n w e e x e m p lify s o m e c a se s o f sy n ta c tic a lly d e te rm in e d stre ss lo ss in D an ish .
In se ctio n 2. w e p re se n t and d isc u ss s o m e p re lim in a ry re su lts o f an e m p iric a l in v e s tig a tio n o f th e rela tio n b e tw e en sy n ta c tic stru c tu re an d p a u se d istrib u tio n in re a d -a lo u d D a ru sh p ro se .
In se ctio n 3. w e d e sc rib e a sp e c ia lise d g ra m m a r fo rm a lism fo r e x p re s s in g s y n ta c tic a s w ell as m o rp h o lo g ic a l and p h o n o lo g ic a l s tru c tu re , an d w e o u tlin e th e p a rs in g s tra te g y u s e d to tra n sfo rm in p u t se n te n c e s to p h o n e tic a lly c o n siste n t an d p ro so d ic a lly a d e q u a te tra n s c rip tio n s w ith sp e cia l e m p h a sis o n h o w to a c h ie v e ro b u stn ess.
1, Syntactic Aspects of the TTS-System
A P P E N D IX 1 is a sc h e m a tic o v e rv ie w o f th e d a ta flo w th ro u g h th e se ria lly c o n n e c te d c o m p o n e n ts w h ic h c o n v e rts strin g s o f A S C II-sy m b o ls to so u n d w a v e s in a ste p w ise fash io n . T h e c o m p o n e n t lab e led S P E Q A L IZ E D P A R S E R (S S P S F O R M A L IS M IN T E R P R E T E R ) ta k e s c a re o f th e le x i- c o -m o rp h o lo g ic a l an d sy n ta c tic a n a ly sis n e e d e d in o r d e r fo r th e s y ste m to e x tra c t su ffic ie n t lin g u istic in fo rm a tio n fro m th e in p u t t e x t T h is c o m p o n e n t, h e n c e fo rth re fe rre d to a s S S P S (S u rfa c e S tru c tu re P a rsin g S y stem ), is th e o n e w h ic h w e h o p e to b e o f m o s t in te re s t to c o m p u ta tio n a l lin g u ists, a n d w e w ill n o t c o m m e n t o n th e o th e r c o m p o n e n ts a t a ll, a lth o u g h m o s t o f th e m a re o f c o u rse m o s t im p o rta n t fo r th e te x t-to -sp e e c h c o n v e rs io n p ro ce ss.
P e te r M o lb æ k H a n se n
In stitu t fo r A lm e n o g A n v e n d t S p ro g v id e n sk a b K ø b e n h a v n s U n iv e rsite t
N ja ls g a d e 8 0
D K -2 3 0 0 K ø b e n h a v n S E -m a il: p m @ q > h lin g .d k
E b b e S p a n g -H a n sse n
In stitu t fo r A lm e n o g A n v e n d t S p ro g v id e n sk a b K ø b e n h a v n s U n iv e rsite t
N ja ls g a d e 8 0
ASCII text: De spiste altid middag kl. 19.
TEXT NORMAUZER (A TRIVIAL PREPROCESSING PROGRAM)
Normalized: de spiste altid middag klokken nitten
SPECIAUZED PARSER (SSPS FORMAUSM INTERPRETER)
Morphophonemic: di,spis*t0,a11+^tidd midd-a klokk-0n,nltt-0n
PHONOLOGICAL TRANSFORMER (SPL FORMAUSM INTERPRETER)
Phonetic: disbi:sdO’alUiD?m’edak]Cg‘'nn'ed‘^n
PHONETIC TRANSFORMER (SPL FORMAUSM INTERPRETER)
parameterized:
PI PI PI PI PI PI PI PI PI -.. PI PI
P2 P2 P2 P2 P2 P2 P2 P2 P2 .... P2 P2
A P P E N D IX 1: T H E D A N IS H T E X T -T O -S P E E C H S Y S T E M :
Pn Pn Pn Pn Pn Pn Pn Pn Pn .... Pn Pn
SYNTHESIZER (SOFTWARE SIMULATION)
Wave image: Frl Fr2...JFr 1649 Frl650
D/A-CONVERTER
Electric oscillations:
LOUDSPEAKER
APPENDIX 2; TASKS IN TEXT-TO SPEECH S \’STEMS (ITS)
AS OPPOSED TO OTHER SYSTEMS (O)
1 . TTS: surfaa structure 1 -> surface structure 2
vs
O: surface structure -> some other structure
Example:
word inventory and order must be identical in input and output
in ITS. (TTS-systems involve both
analysis (identification) and generation.
2. ITS: Semantic structure is often irrelevant
vs
O: Semantic structure is usually essential
Example: semantic structure essential in translation systems
3. ITS: Prosodic features often essential
vs
O: Prosodic features often redundant
Example 1:
"Jens drak mælk" is distinguished from "Jens drak mælken"
both morphologically and prosodically, but for
0-parsers the prosodic difference is irrelevant.
Example 2:
In Danish many but not all stød susceptible
monosyllabic first parts of compounds
exhibit stød-loss. Ilius 'balgulv"
(æmma = > next word unstressed)
(single quote = > next word stressed)
Noun phrase internal constructions of various
semantic subtypes:
a) Determiner phrase ending in indefinite noun:
^t ’stort Jbundt Yriske Vadiser
to /ed lividiøg
b) Constructions with indefinite noun + proper name
j)rofessor Spang-Tlanssen
^lagter X)lsen
^nte ’Agate
/ætter ’Jens
c) Constructions with indefinite noun + numeral
gummer ’et
.indgang 7
Jrappe ’6
d) Constructions with indefinite noun + '^lace name"
/estaurant Den X^yldne Tortun
/Cap Det
Håb
e) Hypotactic proper name phrases:
Jens Teter
,Oie Svendsen
Jens / ’eter ’Jensen
( c o m m a = > n e x t H o r d u n s t r e s s e d ) ( s i n g l e q u o t e = > n e x t w o r d s t r e s s e d )
a ) V e r b w i t h i n d e f i n i t e d i r e c t o b j e c t , i r r e s p e c t i v e o f i n t e r v e n i n g m a t e r i a l :
J e n s i d r i k k e r a l d r i g Y a d ø l J e n s i l e d e r e f t e r ^ n g e
A P P E N D IX 4: S T R E S S L O S S IN \ E R B P H R A S E S
v s
V e r b m t h d e f i n i t e d i r e c t o b j e c t , i r r e s p e c t i v e o f i n t e r v e n i n g m a t e r i a l :
J e n s * d r ik k e r a l d r i g ,s in ^ æ l k J e n s l e d e r e f t e r ’Jp e n g en e
b ) V e r b + a d v e r b i a l c o m p l e m e n t , p o s s i b l y w t h i n t e r v e n i n g d i r e c t o b j e c t :
J e n s iS a tte s i n c y k e l I n d i s k u r e t
v s
V e r b p h r a s e s w t h p e r i p h e r a l lo c a t iv e a d v e r b i a l : J e n s ^ a t t e s i n c y k e l I n d e i s k u r e t ’
c ) A c o m b i n a t i o n o f a ) a n d b ) : J e n s ,s t0v e d e ’b o r d e t ’a f
v s
A . ( T h is l i t t l e i n d d e n t ) / / g iv e s ( a n e w z e s t ) ( t o o u r i n v e s t i g a t i o n )
B . ( C h i c k e n s ) w e r e e a t i n g / / ( t h e r e m a i n i n g g r e e n v e g e t a b l e s ) A P P E N D K 5: V ERB B A L A N C IN G R U L E
I gave th e bo ok to John fo r C h ristm as
APPENDIX 6: PAUSES IN WRITTEN DANISH READ ALOUD ( 16 PAGES )
YES
NO
OBLIGATORY SITES
•
1. A ft e r coordin ated S
65
5
2. A ft e r embedded S
40
2
POTENTIAL SITES
3. Around a p p o s itio n s , quotes
37
8
4. A ft e r coordin ated non-S
25
17
5. A ft e r complex i n i t i a l phrase
42
39
6. A ft e r complex in v e rte d s u b je c t 10
6
7. B efore c la u s e
89
75
8. B efore PP
41
252
TOTAL NUMBER OF PAUSES ‘
343
1 . S o m b a r n e l s k e d e h u n k i r s e b æ r , / / o g h u n t o g im o d p o s e n m e d e n s e lv f ø lg e , d e r f ø r s t b a g e f t e r h a r f o r u n d r e t
m i g / / o g g i k r u n d t b l a n d t d e ø \ r i g e p a s s a g e r e r / / o g b ø d a f s i n r i g d o m . ( D ,2 A )
2 . M e n j e g o p l e v e d e t r e t i n g d e n s i d s t e d a g , h u n d e r s t a d i g f } i d e r m i g m e d u n d r e n . ( D , 1 3 )
3 . V e d H i t l e r s m a g t o v e r t a g e l s e d e n 3 0 . J a n u a r 1 9 3 3 / / m a r c h e r e d e b r u n s l g o r t e m e / / S A - k o r p s e n e / / , i e t f l r e t i m e r s f a k k e l to g g e n n e m p o r t e n . (R ,3 ,5 )
4 . 1 m a n g e l a n d b r u g s e g n e / e r h e l e l a n d s b y e r p å f l u g t / / p å
g r u n d a f m a n g e l p å m a d o g v a n d / / o g a f f r y g t f o r e p i d e m i e r . ( R ,6 ,2 7 )
5 . M e n v e d r e t t e n i M i i n c h e n / / k ø r e r e n p r o c e s m o d e n a f W o lf f s t i d l i g e r e u n d e r o r d n e d e / / g e n e r a l m ^ 'o r S c h u t t . ( R , 5 4 )
6 . S å s k u l l e t o h u n d r e d e å r s d a g e n f o r å b n i n g e n a f B r a n d e n b u r g e r T o r i
d i g 11 v æ r e a n d e r l e d e s p r o b I e m I ø s .( R 4 > 1 3 )
7 a . E n n a b o , d e r ø n s k e d e a t h j æ l p e h e n d e / / b e k l a g e d e s i g o v e r / / a t n å r h a n k o m f o r b i p å v e je n / o g g e r n e v ille h i l s e p å h e n d e / / s å v e n d t e h u n r y g g e n t i l . ( D3 4 1)*
T b . D a h a n e r f a r e d e , a t j e g e n d n u i k k e h a v d e s o v e t / /
i n s i s t e r e d e h a n p å a t g iv e m i g e n i n d s p r ø j t n i n g a t s o v e p å . (D 3 > 2 8 ) D e r f o r s t o d M a r k u s W o l f f n a t u r l i g t n o k h ø j t p å ø n s k e s e d l e n h o s d e v e s tt y s k e m } 'n d ig h e d e r / / v e d g e n f o r e n i n g e n . ( R , 4 4 3 )
N P : : = D E T ? A P * N O U N N O U N > D E F C ' D E H ' ' D E T > D E F C A P > D E F D E T > A N C A P > A N D E T > A G C A P > A G A P > A N C N O U N > A N A P > A G C N O U N > A G D E T > A N C N O U N > A N D E T > A G C N O U N > A G N P > D E F ; T ) E F D ''
D E T : : = Q U A N T ? A R T ? E N U M ? Q U A N T > D E F C A R T > D E F Q U A N T > A N C A R T > A N Q U A N T > A G C A R T > A G A R T > D E F C E N U M > D E F A R T > A N C E N U M > A N A R T > A G C E N U M > A G
Q U A N T : ; = W R D W R D > W c " W K V A "
A R T ; : = W R D ? N P
W R D > W C " W P R O N " N P > W c "VVGEN" A R T > D E F : 'D E F D '' A R T > A : "A"
A R T : : = W R D
W R D > W C "V V D E F R "
E N U M : : = W R D W R D > W c "VVNUM "
F O R E A C H I N P U T S E N T E N C E B E G I N
I N T U T A S E N T E N C E .
S V M T C H T O M O R P H O L O G I C A L M O D E = T O P - D O W N , D E P T H - H R S T , F m S T - R U L E - n R S T , E A C H C H A R A C T E R S U R R O U N D E D B Y
T W O C O N S E C U T I V E V E R T I C E S .
F O R E A C H W O R D B E G I N
P A R S E T H E W O R D A C C O R D I N G T O M O R P H O L O G I C A L P A R T O F G R A M M A R , A C C E P T I N G A T L E A S T 1 A N D A T M O S T 3 I N T E R P R E T A T I O N S .
E N D
A R R R A N G E T H E R E S U L T S A S T E R M I N A L E D G E S I N A C H A R T F O R T H E S Y N T A C T I C M O D E .
S W I T C H T O S Y N T A C T I C M O D E = B O T T O M - U P , L E F T - C O R N E R , E A C H W O R D - R E S U L T S U R R O U N D E D B Y
T W O C O N S E C U T I V E V E R T I C E S .
P A R S E T H E S E N T E N C E A C C O R D I N G T O S Y N T A C T I C P A R T O F G R A M M A R , A C C E P T I N G E X A C T L Y 1 I N T E R P R E T A T I O N .
O U T P U T I N T E R P R E T A T I O N I N
U N E A R I Z E D M O R P H O P H O N E M I C F O R M . E N T )
A P P E N D I X 1 0 : E X A M P L E O F A N A L Y S IS
I n p u t : E n s u r t j e n e r t a b e r a l t i d a n s i g t .
M O R P H O L O G I C A L A N A L Y S IS :
0-1 e n < W N U M A N T JM S A G E N C D E H > 0 - 1 e n , < W D E T A N U M S A G E N C D E F l >
1 - 2 s u r r , < W V I M P S T R 0 > 1-2 s u r r < \ W I M P S T R l >
1- 2 s u r ! < W A D J A N U M S A G E N C D E F l >
2 - 3 t J E n = 0 r , < \V S U B A N U M S A G E N C D E O S T R 0 > 2 -3 t j E n = 0 r < W S U B A M J M S A G E N C D E F l S T R l > 2 -3 ^ E n + O r , O V W I N S T R 0 >
2 - 3 ^ jE n + O r < \ W F I N S T R l >
3 - 4 t a b = 0 r < W S U B A N U M S A G E N C D E n > 3 -4 t a b * 0 r , < \ W F I N S T R 0 >
3 - 4 t a b * 0 r < W V F I N S T R l > d - S a l l + J i ^ t i d d < W A D V >
4 - 5 a l t i d , < W S U B A N U M S A G E N D E H S T R 0 > 4 -5 a l t i d C W S U B A N U M S A G E N D E H S T R l > 4 - 5 a l t i d < W A D J A N U M S A G E N C D E H >
5- 6 a n h ^ I g t , O V V I M P S T R 0 > 5 -6 a n h % s l g t < ^ W I M P S T R l >
5 -6 a n h = s l g t , < W S U B A N U M S A G E N N D E H S T R 0 > 5 -6 a n h = s l g t < W S U B A N U M S A G E N N D E n S T R l >
S Y N T A C T I C A N A L Y S IS :
e n , s u r ^ E n = 0 r t a b * 0 r , a Il+ 4 ^ t i d d a n h = s l g t
U N S U C C E S F U L P A R S E S A R E A V O I D E D B Y 1 ) F I R S T R U L E H R S T S T R A T E G Y
2 ) D E F A U L T R U L E S :
M O R P H O L O G I C A L D E F A U L T R U L E :
S T E M : : = I e t r +
S T E M > M : 'M N S A C M C C O M N P X "
I £ . A N Y L E X I C A L L Y U N I D E N T I F I A B L E P A R T O F A N I N P U T W O R D W I L L D E F A U L T T O
1 ) A N O U N S T E M ,
2 ) O F T H E C O M M O N G E N D E R , 3 ) W I T H P L U R A L I N - E R ,
4 ) W I T H O U T - E - O R - S - A S 1 S T P A R T O F C O M P O U N D
5 ) W r r a S P E L L I N G = M O R P H O P H O ^ ’E ^ ^ C R E P R E S E N T A T I O N .
E .G . A N I N P U T W O R D L I K E 'S M U L P E R N E " W I L L B E O U T P U T A S :
•S m u Ip + O rn O " < > V S U B A N U M P D E F D >
S Y N T A C T IC D E F A U L T R U L E :
S : : = W R D +
l E . "A S E N T E N C E I S A S E Q U E N C E O F W O R D S "
T H I S P R I N C I P L E A L L O W S A N Y D E G R E E O F M O R P H O L O G I C A L A N D S Y N T A C T IC E X P L I C I T N E S S T O B E C O M B I N E D W I T H A G I V E N P R A C T I C A L I M P L E M E N T A T I O N .
