Suppletion in the context of "Surface form"

In grammar, the ablative case (pronounced /ˈæblətɪv/ AB-lə-tiv; abbreviated abl) is a grammatical case for nouns, pronouns, and adjectives in the grammars of various languages. It is used to indicate motion away from something. In different languages it can additionally serve various other purposes, e.g., to make comparisons (in Armenian). The word "ablative" derives from the Latin ablatus, the (suppletive) perfect, passive participle of auferre "to carry away".

The ablative case is found in several language families, such as Indo-European (e.g. Sanskrit, Latin, Albanian, Armenian, Punjabi), Turkic (e.g. Turkish, Turkmen, Azerbaijani, Uzbek, Kazakh, Kyrgyz, Tatar), Tungusic (e.g. Manchu, Evenki), Uralic (e.g. Hungarian), and the Dravidian languages. There is no ablative case in modern Germanic languages such as German and English. There was an ablative case in the early stages of Ancient Greek, but it quickly fell into disuse by the classical period.

In some models of phonology as well as morphophonology in the field of linguistics, the underlying representation (UR) or underlying form (UF) of a word or morpheme is the abstract form that a word or morpheme is postulated to have before any phonological rules have been applied to it. In contrast, a surface representation is the phonetic representation of the word or sound. The concept of an underlying representation is central to generative grammar.

If more phonological rules apply to the same underlying form, they can apply wholly independently of each other or in a feeding or counterbleeding order. The underlying representation of a morpheme is considered to be invariable across related forms (except in cases of suppletion), despite alternations among various allophones on the surface.