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 migrations various historical cultures. The Indo-European languages and cultures spread in various stages. Early migrations from c. 4200–3000 BCE brought archaic proto-Indo-European into the lower Danube valley, Anatolia, and the Altai region. Proto-Celtic and Proto-Italic probably developed in and spread from Central Europe into western Europe after new Yamnaya migrations into the Danube Valley, while Proto-Germanic and Proto-Balto-Slavic may have developed east of the Carpathian mountains, at present-day Ukraine, moving north and spreading with the Corded Ware culture in Middle Europe (third millennium BCE). Alternatively, a European branch of Indo-European dialects, termed "North-west Indo-European" and associated with the Beaker culture, may