or rather; I mean; how should I put it
Used to rephrase or correct what one has just said, often in casual conversation. Can soften a statement or introduce a more accurate description.
彼は優しいというか、甘すぎると思う。
He's kind—or rather, I think he's too soft.
この料理、美味しいというか、クセになる味だね。
This dish is delicious—or maybe I should say it's addictive.
と言うか is the neutral, standard way to say 'or rather', while ってか is its casual, contracted form used in relaxed speech.
From the quotative particle と, the verb 言う (to say), and the question particle か, literally 'should I say?'. It developed into a fixed expression used to rephrase or correct preceding statements.