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
Indo-European s-mobile and Russian "stog". The fact that there is no consistency about which language groups retain the s-mobile in individual cases is good evidence that it is an original Indo-European phenomenon, and not an element added or lost in the later history of particular languages. Sometimes subsequent developments can treat the forms with and without the s-mobile quite differently. For example, by Grimm's law PIE becomes Proto-Germanic "f", but the combination is unaffected by this. Thus the root "", perhaps meaning 'scatter' has two apparently quite dissimilar derivatives in English: "sprinkle" (from nasalized form *"sprenk-") and "freckle" (from *"prek-"). S-mobile is