Base Form

In the UNLarium framework, base form (BF) is the form used to generate all variants (inflections) of a given LRU.

LRUs and BFs

A single concept may have several different realisations in a given language. These variations are of two types:

• Internal variations (inflections), i.e., related to the same lexical realisation unit, such as in “to die”, “die”, “dies”, “dying”, “died”, etc, which are represented by the same lemma “die” as a single LRU; and
• External variations (synonyms), such as “die”, “decease”, “pass away”, “perish”, etc, which are represented by different lemmas and different LRUs in the UNLarium.

As the LRU is the basic unit of the UNLarium, each external variation will correspond to a different entry, but internal variations will be represented inside the same entry and will be generated automatically through inflectional and/or subcategorization rules. In many cases, however, the LRU, which is actually a lemma, is not the most adequate form to guide the process of generating the internal variations. In such cases, we will need a “base form”, i.e., a lexical realisation that is more suitable for automatic processing.

Consider, for instance, the case of the LRU “take into account”, which is actually a discontinuous item, since we can have any noun phrase between “take” and “into account”: “take that into account”, “take it into account”, “take the decision of proliferating dictionary fields into account”, etc. In order to be prepared to process all those possibilities, we have to create a different lexical entity, which will be exactly the base form. In the case of “take into account”, the base form will be “take”. From the base form, we will be able not only to associate the LRU to an existing inflectional paradigm (“take”) but also to treat discontinuity and order issues through simple and deterministic generation rules.

How to create a BF

The BF is the same as the LRU, except in the case of compound or complex LRUs that involve infixation.

Compound and complex LRUs are LRUs that contain more than one word (whether concatenated or separated by hyphen or spaces), and where the BF is often indispensable because variations cannot be generated by simple prefixation and/or suffixation rules. In these cases, the BF is different from the LRU: it will correspond to the lemma of the longest common denominator between all the possible variations of the LRU.

The use of BF

The use of BFs is derived from a practical limitation rather than from a logical necessity. In order to be efficient and to avoid overcharging the system, generation rules have to be as general and few as possible, what limits considerably the possibility of creating infixation rules. The alternative is to reduce infixable compounds and complex LRUs to the longest common denominator (i.e., to “hyper-regularise” them) in order to treat infixation as a special case of prefixation or suffixation.

In English, the use of BF is limited to phrasal verbs (such as "give in" and "bring (sth) back”) and verbal phrases ("play with fire"). The need of BFs is more noteworthy in highly-inflective languages where compounds and complex LRUs may be reordered or infixed. Consider, for instance, the case of the LRU “lingua” (= “language”), in Latin. As a case-inflectional language, Latin normally has 12 different forms for each noun:

case	singular	plural
nominative	lingua	linguae
vocative	lingua	linguae
accusative	linguam	linguas
genitive	linguae	linguarum
dative	linguae	linguis
ablative	lingua	linguis

For single-word LRUs, as “lingua”, the process of case-inflection is relatively simple, because it is extremely regular and will always correspond to a suffix. In complex LRUs, however, the process can be quite more complicated, because of infixation and agreement. For “lingua franca”, for instance, we will have again 12 different forms, but generating them is no longer as simple as adding suffixes to the right of the LRU.

case	singular	plural
nominative	lingua franca	linguae francae
vocative	lingua franca	linguae francae
accusative	linguam francam	linguas francas
genitive	linguae francae	linguarum francarum
dative	linguae francae	linguis francis
ablative	lingua franca	linguis francis

In order to avoid listing all variations of “lingua franca” inside the UNLarium or creating a very specific rule which would apply only in this case, we reduce “lingua franca” to “lingua” and create a special (subcategorization) rule for generating “franca” later on. The LRU will be then “lingua franca”, but the BF will be only “lingua”.

Examples

Lexical Realisations	Lexical Realisation Unit (LRU)	Base Form (BF)
apple, apples	apple	apple
city, cities	city	city
glasses	glasses	glasses
rosa, rosae, rosam, rosas, rosarum, rosis	rosa	rosa
beautiful	beautiful	beautiful
hermoso, hermosa, hermosos, hermosas	hermoso	hermoso
sum, es, est, sumus, estis, sunt, eram, fui…	esse	esse
part of speech, parts of speech	part of speech	part of speech
skinhead, skinheads	skinhead	skinhead
give in, gives in, gave in, given in, …	give in	give
pars orationis, partes orationes, partem orationis, partis orationis, …	pars orationis	pars
bring [sth] back, brings [sth] bak, bringing [sth] back, brought [sth] back, ...	bring back	bring
play with fire, plays with fire, playing with fire, ...	play with fire	play