For what reason did you do that? = για ποιο λόγο το έκανες αυτό; His speech was littered with mistakes = ο λόγος του ήταν γεμάτος λάθη
You can't really mistake one for the other - context is king! :D
That still applies to "Για ποιο λόγο το έγραψες αυτό;" which could be either speech or reason, because the people in the conversation would know if they are talking about Thursday's speech or a misjudged situation. Of course, if you mean 'reason' and it's unclear, you can always clarify by asking 'why' .:)
Theoretically there could, just as English could have two words for "know", one for knowing information (like German wissen, French savoir, Spanish saber) and one for being acquainted with people (like German kennen, French connaître, Spanish conocer).
But English doesn't, even though to (say) a German speaker, "I know where Paul is going" is a different thing than "I know Paul".
Logos. Mm. I'm loving discovering so much about my own language through doing this Greek. Similarly with doing Norwegian, which has another set of related roots to English, coming from a different direction. I have an old Greek Bible, and if you have a bit of writing, whatever that might be, that you know in your own language, you can muddle along and understand, and it's strangely exciting realising that zoo comes from the Greek for life and animal, etc. It's like shining a light into a mass of ignorance :-) Thank you Duo. I have to say, I initially found the Greek here very very hard going. I had a break and went back and did the early parts again and again, getting more confident in the alphabet, etc, and just doing a small amount most days, and it is beginning to work in my little brain- I'm starting to remember the new words, the connections are happening, and I'm enjoying it... so for anyone finding it tough, to go back over the most basic parts of all can make a big difference.