Plato is probably the number one philosopher for mispronunciation. Indeed, an entire country seem to think it is correct to call him:
However, his name is not play-doh. The emphasis should be upon the T rather than flattening it. Thus:
Pl'ay-Toe
Of course, Greeks might point out that we are all mispronuncing the word and it should sound more like:
Plateau.
I'm not so sure about that myself. Not that they don't know their own language. They do.
Whatever, just stop calling him Play-Doh.