# you with the tongue. If you utter speech

or "you. If with the tongue you utter speech"

# with the tongue

The word "tongue"refers to all the parts of the body which a person uses in order to speak. 

# If you utter speech that is not clear

"If you speak in a language that people do not know"

# how will what is said be understood

"how will anyone understand what you have said"