On the -θ- in Greek οἶσθα 'you know' < *uoid-th2e.

The article offers a new solution to the unexpected occurrence of -θ-, rather than **-τ-, in οἶσθα 'you know' < *uoid-th2e. It is proposed that this form first became *woitsta, as expected, and then underwent the same development as seen in *pst > *phsth (> phth, cf. *seps-tos > ἑφθός 'boiled') and *kst > *khsth (> khth, cf. *h1eḱs-tos > ἐχθός 'outside'), i. e. *tst > *thsth, before losing the first stop of the cluster. The isolation of the ending -θα meant that there was no source for restoration, unlike in all other cases of *tst (e. g. ἴσ-τε 'you (pl.) know', ἄισ-τος 'unseen'). Incidentally, the proposed sound law by which all voiceless stops in TsT-clusters, including those which were later simplified to sT, were aspirated by *s also allows us to straightforwardly trace ἔσχατος 'uttermost' back to *h1eḱs (*ἔξ-κατος > *ἔχσχατος > ἔσχατος), to consider the possibility that ἐσθίω 'to eat' was based on the 3sg.pres. *h1ed-ti 'eats' > *ἔσθι rather than on the imperative, and to connect the word group of αἰσχρός 'causing shame' < *h2eid-sk- with that of αἰδώς 'shame' < *h2eid-. [ABSTRACT FROM AUTHOR]