I think the letter K has a bit of an ego. It starts many great words like kite and kitty and kale.
But, then...it butts in where it's not needed and leads words like knee, knife, knob, knit and knoll. Doesn't that seem a bit pushy? Nee, nife, nob, nit and noll would still be legible without the K. The K only looks correct because we learned to spell these words with the K in place. But, really...who allowed the K to head up the line like that?
I think people who are learning English as a second language must find the superfluous K to be the most problematic letter to deal with. Sometimes you hear it; sometimes you don't. There's no rhyme or reason to why it leads some N-sounding words and does not lead not others.
Like knever. Or kno. Although it does lead know. See how squirrelly this is?
Let me know if you agree with me. Or knot.