Semantically Governed Machine Translation of BE-clauses with Ad-

verbs and Prepositional Phrases. Demonstration of a Ring-Model for German~English, English/German

including Analysis-Synthesis, Transformation, Transition,

Generation. Klaus G~nther Schweisthal, Forschungsgruppe LIMAS, Bonn Research in methods of lexicalization, classification, synthesis, transformation, transition, and generation, been carried on independently in the German and English at LIMAS, has recently been consolidated for the purpose of constructing a Ring-Translation-Model for German/English, English/ German. This model has to meet the following requirements: I. It must;produce a translation which is identical in meaning

to the original and stylistically acceptable. 2. Some Of the difficulties which have heretofore appeared in

machine translation must be resolved. The starting point (Figure I) is a German adverbial phrase, which is to be analyzed and then converted into a factor formula by means of a morpho-nomo-transformation. An explicative homo-homotransformation together with prepositional governing factors then expand the factor formula for the adverbial expression into a formula for a prepositional phrase, which in turn becomes expressible through a nomo-morpho-transformation. The factor formula for the German prepositional phrase is converted into an English factor formula according to the coordinator's system of maximum agreement. This takes place through a nomo-nomo-transition if the identical factor formula is present in English, otherwise through a nomo-~omme~ra~afQ~mation. A nomo-morpho-tr&nsformation then creates an expressible English prepositional phrase which is semantically equivalent to the German. The factor formula for an English adverbial phrase is made possible by a reductive nomohomo-transformation plus a nomo-morpho-transformation. The last step of the cycle again takes place in the coordinator. The factor formula for the English adverbial phrase is converted into the corresponding formula for the German adverbial phrase by means of transition or a homo-homo-transformation. The morphological realization of this factor formula is identical to that of the initial German adverbial phrase. A sample output of the ring would be: vater Father Vater ist

is ist drinnen .... Vater ist innerhalb des Hauses .... inside (of) the house .... Father is inside .... drinnen. The automatic reversible process of the ring model is determined by several association lists and function matrices. At first a - I and analysiswhich has

sections i ~ ~ .. I; ~ I~. I ,r ,, o I"1" z "3 U ~"! O" q P ' igl I.~1 I1~ ~ U ~'i"-I i " ~ I~i /"

....

{1 0 0 ¢ m D , : ~ lexicon of German Jand English semantic factors is necessary. This list lists of illustrated

forms the upper the German-English

three different row for

words

types the necessary nomo'association (Figure 2). In this figure are of semantic association. List A/D illustrates the association of the factors to the German adverbs, A/P to the German prepositions, and N/D to the various German noun classes. In a strict sense the noun class association is to be specified once again according to the two syntactic functions of the noun in the sentence, i.e. BE-subject* and BEcomplement*. ~For English ner in the independent

the association has been organized in a similar manlists A/S, P/E, N/S, but in such a way that they are

of German. An example may make this a little more clear. Assume that A/D1 is the German adverb "drinnen" and the factors I, 3, 5, 8, are coded symbols for the factors 0r___~t, La~e, Einschlu~, Bet~hung der einschlie~enden Grenzen, Hinweis, then according to the'~prinQiple of maximum agreement we are able to determine the same factor combination Place, Location, Interior, Accent on boundaries, Reference, in A/E under 1, which in English is the word With this same set of factors we find that in P/E according to maximum agreement the results which are expressed as "innerhalb" and "inside the lists

are P/D I

of". In the list N/D all five preposition factors appear in class B, so that if we were to choose as BE-complements Garten or Haus the resultant phrase would be: innerhalb ten--~Hauses--~. Because this set of factors also appears in N/E, it is possible through transition to produce the English phrase "inside of the garden (house)". In view of this schematic arrangement one might think that it is possible to associate all @erman prepositions word for word w£th English prepositions. (This method was used frequently in the early days of machine translation resulting in untold difficul' ties.) Such word for word association is almost 100 % possible for the prepositions of place. But if, for example, we are dealing with the German word nach, which can either be P/D~ plus factor 7 (Zeit) or P/D h plus factor 2 (0rt), we are not-able to make a direct association, but ~ must decide according to the method of maximum agreement whether English ,after" or "to" is meant. The corresponding words in A/D and A/E would be "danach"-"dorthin", and Wafter that"-"there". See accompanying sheet for LIMAS terminology - 9 "inside,. P/D a~d and P/E1, the noun the words

des Garunder B NOMO-ZUORDNUNGEN VON WOERTERN DE UTSC H - E NG LISCH Inhaltfaktoren . Sprache Wortarten - - D E D E D E m Figure2 / Semantic Factors I m~ m x - - -.... Lm

2 3 4 Adv. ±m~m~ 2

(Liste A/D)~m~ --xm~ Adv. (List A/') Pr~p. ( Liste P/D) ~~m

Prep. ! m (List P/E ) ~m~m--m .. ~m m i _m A ~ Nomen Inhalt -ira ..... mi2_ ._~.. m_--m~m m

Klassen (Liste N/D ) t

m A Forschungsgrurpe LIMAS 67 ,-immmm ~m_m J ~m 1 Ym "~'- ~ ,zm -imr-m_ m~m m---~ = .... -m~m-mm mE___ The selection of the fadtors Place and Time for the respective noun classes in the noun class lists N/D and N/E would allow the generation of the phrases: "nach dem Mittagessen", ,uach K5ln", and "after lunch", "to Cologne". Already it is evident how our system differs from those of earlier machine translation projects. In the nomo-association list we have established the prerequisites for generation, transformation and transition. In the i middle function matrix P/D - P/E (Figure 3) of this diagram are contained the restrictions as to which prepositions may combine with which semantic noun classes to produce a meaningful Be-complement. A quick glance shows that the preposition-noun relakionship is differentiated in various ways. This is one proof for the necessity of classifying nouns according to function or semantic classes. This can be illustrated in the following the preposition column are replaced by of noun classes by a representative of I. 2. ~. n. innerhalb rechts nach (Zeit) vor (Abstr. Ber.) A-rater B-Garten x x x Using the lexicon the permitted BE-complements can be programmed from this matrix. The various possibilities for generating meaningful adverbial BE-clauses can be seen in the matrix N/D - A/D. Here again the necessity of using noun classes is evident, even though some noun classes in the matrix (A, B, C,) appear to be similar. Example: Vater ist drinneu

drau~en

rechts

but not danach But with Mittagesseu all four adverbs are possible: drinneu drauBen rechts danach A further prerequisite for ses containing prepositional BE-subject noun class with , the generation of meaningful

phrases is the coordination the BE-complement noun class. BE-clau-

of the The matrix Sntr/N/D - SnE/N/D supplies the necessary information. -5-

Bxample. The codes in prepositions, and the row each class. C-K~In --~Mitta~- Q-Gedanke

essen x x X X NOMO ZUORDNUNG VaN SATZGLIEDERN DEUTSCH- ENGLISCH DEUTSCH ENGLI SCH ERLAUBTE ADVERBIAL-SAETZE

SnE

1 2 3 --4,,,I II A YXX PER M ITT ED A DVERBIAL C LAUS ES B iW'× iW Sn tr C WY× J Matrix: ./D--A/D ERLAUBTE PRAE POS. Seinserg~nzu rig PHRASEN Matri x: P/D ERLAUBTE

FUNKTIONI Sntr /N Inh. Klasse -Sn E/N Inh. Klassen

Matrix: J Figure3 Q p ' , tr u c .~ ° ×XXX × A B C ×X X,X× Q × X A B C ~ Q X "~ X'~ X ~ X X ~ X ~ l X Forschungsgruppe Matrix: N/E -- AlE PERMITTED PREPOS. PHRASES Matrix: PIE -~/E PERMITTE D FUNCTIONS SeS/Sem. :lass- Noun bc/s~m. Noun Classes M a,,i.: L I MA S 67 J a BE-subject from the noun class"abstract"is comwith a BE,complement from the same class. Die Der Der Der Idee ist hinter dem Gedanken Gedanke ist hinter dem Garten Garten ist hinter dem Hans Garten ist hinter dem Mittagessen of these factors have been formalized and all conwere illustrated in the matrices are taken into it is possible to set up a final function matrix. (father) (house) (Cologne) (lunch) (in front of) dem Mittag-

essen dem Gedanken For example, patible but but No~ until ditions consideration This matrix of meaningful For example: A is B C 9 then NPN/D NPN/E In order to also in practise, we have compiled a German and English lexicon consisting of 16 prepositions, 16 adverbs, and one noun from each of the fim~noun classes. The upper row of the homo-association chart, which was seen in figure 2, is filled with over 30 semantic factors. The outputs show that the ring model works satisfactorily. With the aid of these matrices (Figures I - 4), a semantically equivalent German/English, English/German translation can be executed for all the cases in which the function matrices in both languages are identical in structure, e.g. (NPN/D - NPN/E .... (transition). For those cases in which the function matrices are not identig only

not

not

all which to be • --9 --÷ --@ --4 --@ --@ --@ --9 --~ --9 A A A A A A A A A A then aids the translation process in the generation

BE-clauses with prepositional phrases.(Figure 4) replaced 9 A --7 9 B --) 9 C --) 9--~ 9 Q 9 A --) 9 B --) 9 C --9 9 ~-~ 9 Q show that this modei exists not only on paper but by Vater

Haus

K~in

Mittagessen (action) vet (place) Vater ist vet dem Vater

vor dem Haus

vet KSln (not permitted!) (not permitted!) Father is in front

in front

in front !not permitted!~ (not permitted!) Vater ist vet Vater ist vet

of the father

of the house

of Cologne Father is in front of lunch Father is in front of the

thought ~i _ ~ ,~ Z /'}L O. ~ u Z <3 i,0 oO i 1:9 O. O. O~ O~ j <{ rn 0 0 i. b E x_ o I cal (NPN/D I N'PN/E), the proper translation is insured by means Of au auxiliary program. This takes place through verbalization of the semantic factors of the source language in the target guage. lanFor example: The English sentence father there gram, KSrper If a gram eig. ded with the possibility of such the reverse process - in case it German adverb can be selected for position + p~-onoun. a transformation, so that in should be necessary - the proper

the English combination pre-

cannot be translated into is no corresponding matrix however, makes possible the

des Vaters German adverb will create a dahinter ....

The candle is inside (of) German as it now is because NPN/D. The verbalization pro-

translation Die Kerze ist im the counterpart, an auxiliary proeingeschlossen. has no English semantically equivalent prepositional phrase, behind it. All German adverbs must be provii -- 9 -Some Terms of Ll~hkS-Terminolo~r:: 1. Transformation a) b) Morpho-transformation: A change within the morpho-structure involving formal constituents. Morpho-semantic-transformation: A change within the morpholevel involving those semantic factors which are referred to as "Denkweisen". These are: sentence constituent,framed, stressed, cyclopic, nominal, actional, and designative. c) Zorpho-nomo, and nomo-morpho-transformation: A transfer from the morpho-level to the homo-level or vice versa. (This is similar to a change from the deep structure to the surface structure and vice versa in TransformationalGenerative Grammar.) d) 2. Nomo-nomo-transformation: I) Within the same language: A change of the factor formula

by means of exchange, addition, or elimination of cer-

tain factors. 2) Between the ~ource language and the target language: The

factor formula of the source language is not acceptable

in the target language, and must therefore be reshaped. Transition The simple transfer of a factor formula from one metalanguage into another. 3. Explication To make explicit a semantic factor in a sentence which contains no morpheme to represent that factor. The morpheme can be lacking for three reasons: a) ellipsis b) non-expressed context relations c) It is therefore sis explication, tor explication. ever, be combined. a combination of semantic factors which are understood but not expressed. important to differentiate between a) ellip-

b) context-relation explication , and c) fac-

These three types of explication can, how4. Verbalization The process of verbally expressing a semantic factor within the morpho~level which has been determined through explication. _ - 1 0 ~. Reduction The opposite of explication, i.e. a factor formula of the language is not permitted to be verbalized. The factor is really eliminated, but is implied within the morpho-level. metanot 6. ExplicatinG-transformation a) b) Explicating nomo-nomo-transformation: A semantic factor which has been determined through explication changes the factor formula. Explicating nomo-morpho-transformation: The semantic factor becomes verbalized. Faktorenformel Funktionsmatrix Inhaltfaktor ist-Satz Nomeninhaltklasse Seinstr~ger (Sntr) Seinserg~nz~ng iSnE) Traduktion (Trd Transformation (Tr) Zuordnungsliste Criteria for "meaningful" sitional phrases: a) Approximately 40,000 various sources. b) c) A smaller collection Interviews with several native speakers of English from England and America. -11-

factor formula

function matrix

semantic factor . Be-clause

semantic noun class

Be-subjectc(BeS)

Be-complement (BeC)

transition

trmnsformation

association list BE-clauses with adverbs and prepoexamples of modern German taken from of English examples.