-U-

Umlaut
PHONOLOGY/MORPHOLOGY: the phonological process in which back vowels or diphthongs are fronted due to (a) a following front vowel, or (b) a specific morpheme or morphological class. EXAMPLE: a well-known example is German umlaut. Plural nouns can be formed in several (unpredictable) ways. One possibility is fronting of the base vowel: Apfel:Äpfel and Bauch:Bäuche.
LIT. Lieber (1980), Spencer (1991).

Unaccusative verb
Special kind of °intransitive verb. Semantically, its subject does not actively initiate or is not actively responsible for the action of the verb; rather, it has properties which it shares with the direct object of a transitive verb (or better, with the grammatical subject of its passive counterpart). EXAMPLE: in English arrive, die and fall are unaccusative verbs. Another term is ergative verb.
SYNTAX: verb that assigns no °external theta-role and no structural °Case. Its argument is in object position at D-structure, but has to move to subject position in order to receive (nominative) Case (from INFL). The syntactic behaviour of unaccusatives differs in various ways from non-unaccusative intransitive verbs (°unergatives). In languages that have a distinction between the perfective auxiliaries 'to be' and 'to have', the unaccusatives take 'to be', while the unergatives take 'to have'. EXAMPLE: the Italian sentences in (i) and the Dutch sentences in (ii) are examples.

(i)    a  ha telefonato Gianni
	  has telephoned G
       b  è arrivato Claudio
	  is arrived C

(ii)   a Jan heeft getelefoneerd
   	 J has telephoned
       b Klaas is gearriveerd
	 K has arrived
Furthermore, unaccusatives cannot be passivized, as opposed to unergatives (in languages with impersonal passives). This is shown by the contrast between the Dutch (iii) and (iv).
(iii)	er wordt door Jan getelefoneerd
	there is by J telephoned
(iv)   *er wordt door Klaas gearriveerd
	there is by K arrived
In Italian, a further diagnostic to distinguish unaccusatives from unergatives is the possibility of ne-cliticization.
LIT. Perlmutter (1978), Perlmutter & Postal (1984), Burzio (1981, 1986), Belleti & Rizzi (1981), Den Besten (1985), Hoekstra (1988), Grewendorf (1987).

Unary connective
°Connective.

Underspecification
PHONOLOGY: the theory that underlying representations are not fully specified i.c. that predictable information is not underlyingly present. EXAMPLE: in English there is no lexical distinction between aspirated and non-aspirated stops. Still there is a phonetic difference between the [p^h] in [p^h]in and the non-aspirated [p] in s[p]in. Underspecification theory expresses this by assuming that underlyingly both p's are not specified for aspiration. The aspiration feature is later (post-lexically) specified by a context-sensitive rule inserting [+spread glottis] at the beginning of a syllable; the non-aspiration is a consequence of a universal rule which inserts [-spread glottis] in all other contexts. °Structure preservation, °structure building rule.

Unergative verb
Special kind of °intransitive verb. Semantically, unergative verbs have a subject perceived as actively initiating or actively responsible for the action expressed by the verb. EXAMPLE: in English run, talk and resign are unergative verbs. In syntax, unergative verbs are characterized as verbs with an °external argument. See °unaccusative verb.
LIT. Perlmutter & Postal (1984), Burzio (1986).

Uniqueness
SEMANTICS: a distinguishing property of singular definite descriptions. The sentence The present king of France is bald entails that there is a king of France (existence) and that there is exactly one (uniqueness). A point of debate has been the question whether existence and uniqueness should be treated as part of the assertion (as Russell did) or as a presupposition (as Strawson proposed).
LIT. Russell (1905), Strawson (1950).

Unitary Base Hypothesis (UBH)
MORPHOLOGY: a hypothesis proposed by Aronoff (1976) and Scalise (1984) which says that Word Formation Rules may only operate over a single type of syntactically or semantically defined base. This means that there may be affixation rules which attach an affix to the class of 'transitive verbs' or to the class of 'abstract nouns', but rules which attach an affix to both the class of 'Transite verbs' and the class of 'abstract nouns' are ruled out.

Universal quantifier
SEMANTICS: a logical operator of predicate logic, written All, which makes it possible to express that all entities in the °universe of discourse have a particular property. In (i), it is used to express that every entity has property P.

(i) All(x) [ P(x) ]
It is a standard assumption that natural language expressions such as each girl and everyone contain (or are) universal quantifiers.
LIT. Gamut (1991).

Universe of discourse
SEMANTICS: the set of entities we are talking about when using a sentence. Also called domain of discourse. EXAMPLE: in using (i)a the universe of discourse can be all human beings (and the sentence is most certainly not true), or it may be a restricted set of human beings (and the sentence may very well be true). In (i)b the universe of discourse has been explicitly restricted by the adjunct in this room.

(i) a  everyone is happy
    b  everyone in this room is happy
LIT. Gamut (1991).

Upward monotonicity
SEMANTICS: a property of °determiners and °quantifiers in °Generalized Quantifier Theory. A determiner D is left upward monotone (or left monotone increasing or persistent), if D(A,B) implies D(A',B) where A' is a superset of A. It is right upward monotone (or right monotone increasing) if D(A,B) implies D(A,B'), where B subset B'. EXAMPLE: the D some is left upward monotone and right upward monotone; see the validity of the implications in (i) and (ii) respectively:

(i)  If some dogs walked, then some animals walked.
(ii) If some dogs walked rapidly, then some dogs walked.
Because the interpretations of CN' and VP' are extensions of the interpretations of CN and VP respectively, the corresponding determiner or NP is also called closed under extension.
LIT. Gamut (1991).