I often hear people who have English as their second language use "How you say..." or "How do you say..." when they can't think of a certain word in English. For example, "The car was... how you say... blue!"
何て言うか You're basically asking what's a sorta filler word thing you use when you're thinking of what you wanted to say, like "what was it..." or "uhhh what's it called" or just "uhhhh *snaps fingers*", right? If you watch the old George and Keiko shows, you can often hear Keiko use 「何て言うか」(なんてゆうか) or just plain 「なに?」in that way, so I guess it's just that?