Phonetic: "Be'oz'ney kseel al te'da'ber, kee ya'vooz le'se'chel mee'leicha."

Translation: In the ears of a fool do not speak for he will scorn the wisdom of your words.

Meanings:

• One of the most crucial things in conversation is measuring and knowing whether the 'vessel' of the listener - his capacity to listen, hear, comprehend and absorb, is adequate and ready to accept (or consider) the words of the speaker.
  
• When a listener is not ready for your words, instead of giving you a positive feedback she may try to defend herself and her ego by looking down upon you and your words, resulting in feelings of anger and insult in yourself.
  
• Hence it is advisable to evaluate the listener capacity of comprehension beforehand. In case found insufficient - just stay silent or change the subject matter and the choice of words accordingly.