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 verbs "present" and "imperfect". The traditional terms are based on the names of the corresponding forms in Ancient Greek (also applied to Sanskrit), and are still commonly encountered. Furthermore, there is a separate secondary-verb form commonly known as the "stative" and marked by a suffix "*-eh₁-", which has no connection with the stative/perfect described here. The following table shows the two systems of terminology. It must be noted that in Proto-Indo-European, the aspects had no tense meaning, like they did in the later languages. In Ancient Greek, for example, the perfect carried the meaning of a state resulting from a past