Aspirated consonant:

The other Ancient Greek dialects, Ionic, Doric, Aeolic, and Arcadocypriot, likely had the same three-way distinction at one point, but Doric seems to have had a fricative in place of /tʰ/ in the Classical period, and the Ionic and Aeolic dialects sometimes lost aspiration (psilosis).

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Rather than /tʰ/, what did the Doric dialect have in place during the Classical period?
fricative