Is it correct to say "How many languages do you know how to speak?"
Is it correct? "How many languages do you know how to speak?" I am confused by words "how to speak".
1. How many languages do you know?
2. How many languages do you know to speak?
3. How many languages do you know how to speak?
Thank you for your help.

Question

Is it correct to say "How many languages do you know how to speak?"
Is it correct? "How many languages do you know how to speak?" I am confused by words "how to speak". 
1. How many languages do you know?
2. How many languages do you know to speak?
3. How many languages do you know how to speak?
Thank you for your help.

Answer

Items one and three are both completely correct and very common.

The second sentence would be very unusual but would certainly be understood.

A simple formulation which you haven't used is this:

"How many languages do you speak?"

In other words, it isn't necessary to use the verb "to know," to ask this question at all.

Answer

how many languages do you speak it's better