How is "Lev Chacham Yaskil Pihu"?
Rashi: His heart teaches his mouth to speak clearly.
R. Yonah: Before he speaks, he thinks and contemplates.
Malbim: Chachmah became a Kinyan to him, to the point that he is called Chacham Lev. This heart makes wise his mouth, which hints to speech of Chachmah. When he speaks in the laws of Chachmah, he will have Ru'ach of Sechel to understand their Emes.
Why does it add "v'Al Sefasav Yosif Lekach"?
R. Yonah: When he speaks, his heart adds teaching to his lips' words, in addition to the good reasons and Da'as that he thought before his lips speak.
Malbim: When his lips speak the laws of Chachmah to clarify them with proofs of Da'as, to which the lips hint, he adds teaching - "u'Mesek Sefasayim Yosif Lekach" (21).
