Indo-European copula copula (with corresponding voiceless and voiced fricatives) existed side by side in Germanic, and the involvement of a separate root "" is unnecessary. The root "*(s)teh-" meant "to stand". From this root comes the present stem of the so-called "substantive verb" in Irish and Scottish Gaelic, "tá" and "tha" respectively. On the absence of the initial s- in Celtic, see Indo-European s-mobile. In Latin, "stō, stare" retained the meaning "to stand", until local forms of Vulgar Latin began to use it as a copula in certain circumstances. Today, this survives in that several Romance languages (Galician-Portuguese, Spanish, Catalan) use it
Proto-Indo-European nominals verbs. A lexical word (as would appear in a dictionary) was formed by adding a "suffix" (S) onto a "root" (R) to form a "stem". The word was then inflected by adding an ending (E) to the stem. The root indicates a basic concept, often a verb (e.g. 'give'), while the stem carries a more specific nominal meaning based on the combination of root and suffix (e.g. 'giver', 'gift'). Some roots seem to have no definable meaning, as in 'father'; and some stems cannot clearly be broken up into root and suffix altogether, as in 'bear'. The ending carries grammatical