Derived from an obsolete verb tekt (“to rush, to run, to flow”), from Proto-Indo-European *tekʷ- (“to run, to flow”), whence also tecēt (“to flow”); the meaning changed from “moving quickly” to “working hard.” The e → a change parallels tecēt, taka (“path”). The t → č change (palatalization) is not regular in Latvian, which suggests either an expressive or affective feature (compare aiča, meiča, from aita (“sheep”), meita (“girl, daughter”)), or the former existence of parallel forms with a and e: *tekls + *takls → *tʲakls; compare dialectal čekls ([tʃækls]). Note that the same stem also palatalized in Tocharian cake (“river”), Avestan 𐬙𐬀𐬐 (tak, “stream, torrent”); since both the ancient Balts and the Tocharians were in direct contact with Northern Iranian tribes, this palatalization may be the result of Iranian influence. Cognates include Sanskrit तकुः (tákuḥ, “hurried, quick, mobile”), तक्वः (takváḥ, “fast, quick”) (compare तक्ति (takti, “to hurry”), Ossetian тӕх (tæx, “quick stream, torrent; quick, fast, turbulent; dedicated”), Ancient Greek ταχύς (takhús, “swift, quick, agile”).