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Morphology and FSTs

Morphology and FSTs. Morphology is the study of the way words are built up from smaller meaning-bearing units, called morphemes . A morpheme is defined as the minimal meaning-bearing unit in a language. E.g. The word “ gatos ” has two morphemes: “ gato ” and “ -s ” .

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Morphology and FSTs

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  1. Morphology and FSTs • Morphology is the study of the way words are built up from smaller meaning-bearing units, called morphemes. • A morpheme is defined as the minimal meaning-bearing unit in a language. E.g. • The word “gatos” has two morphemes: “gato” and “-s”.

  2. Morphology and FSTs • Two important kinds of morphemes are: Stems and affixes. • Stem: is the main morpheme of the word, supplying the main meaning. • Affixes: add “additional” meanings of various kinds. • Affixes are further divided in: prefixes, suffixes, infixes and circumfixes. • Prefixes: precede the stem. • Suffixes: follow the stem. • Circumfixes: do both precede and follow the stem. • Infixes: are inserted inside the stem.

  3. Morphology and FSTs Examples: English “unable” is formed by the prefix “un-” and the stem “able”. Spanish “niños” --> stem “niño”, suffix “-s” “damelos” --> stem “da”, suffix “-los”, infix “-me-”

  4. Finite State Morphological Parser • Features: morphological features specify additional information about the stem (e.g. plural, singular, masculine, feminine, 1ra persona, 2da persona, 3ra persona)

  5. Derivational Morphology Derivation is the combination of a word stem with a grammatical morpheme, usually resulting in a word of a different class. Common derivations in English Nominalization is the formation of new nouns from adjectives and verbs.

  6. Derivational Morphology Adjectives can also be derived from nouns and verbs:

  7. Finite State Morphological Parser In order to build a morphological parser we need at least the following: • Lexicon: the list of stems and affixes, together with the basic information about them. • Morphotactis: the model of morpheme ordering that explains which classes of morphemes can follow other classes of morphemes inside a word. • Orthographic rules: these spelling rules are used to model the changes that occur in a word, usually when two morphemes combine.

  8. Finite State Morphological Parser

  9. Finite State Morphological Parser Exercises: • Identify the tokens that occur in the following expression (tipical of almost any programming language) and create REs that generate each of them: f(x)=3.1416*X08+sin(X08/2.5)-X08@231

  10. Spanish General Knowledge (Quiz 1) • Distingue los diferentes monemas: • Rehabilitáramos: • Expatriación: • Pañuelitos: • Reforestábais: • Antiglobalicacion: • Vivificación:

  11. Spanish General Knowledge (Quiz 1) • Indica el tipo de lexema que son las palabras de las siguientes frases: • El estanque del parque está siempre lleno de pájaros exóticos. • A mi amigo Félix le gusta coleccionar cosas raras. Andrés se levantó ayer • un poco tarde y Lucía hizo lo mismo.

  12. Spanish General Knowledge (Quiz 1) • Indica a qué clase de palabra pertenece cada una de las palabras marcadas en las oraciones: • Mi coche es rojo. • La rubia era mi prima. • Los coches  corrían mucho. • Juan y Luis siempre han sido amigos.

  13. Spanish General Knowledge (Quiz 1) • Busca el femenino de las siguientes frases: • El presidente ecologista • El psicólogo dormilón • Mi cariñoso jefe • El panadero alegre

  14. Spanish General Knowledge (Quiz 1) • Este texto periodístico tiene errores: hay adjetivos que deben ir después del sustantivo. Corrígelo.  El presidente de G. ha emprendido un largo viaje diplomático por lejanos países, acompañado de su ministro de exteriores asuntos y de su joven esposa. Durante los últimos días se han producido ya numerosas anécdotas. En la inauguración de un industrial edificio, por ejemplo, alguien entregó a la esposa del presidente un redondo objeto que resultó ser un japonés reloj de pared. Pero también ha habido malos momentos. Cuando iban en el oficial coche a la inauguración de un nuevo edificio por una estrecha carretera de montaña, el coche del presidente sufrió un pequeño accidente y chocó contra una vacía casa.

  15. Spanish Morphology For a detailed account of Spanish morphology consult the following page: • Universidad de Valéncia, España http://mural.uv.es/morfesp/ • http://www.profesorenlinea.cl/castellano/Analisis_morfologico.htm • http://www.vicentellop.com/apuntes_gramatica/apuntes.htm

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