1)
Who has "Sefas Sheker"?
1.
Rashi: It is the seed of Esav - they trap people with their mouths, with evil claims.
2.
Radak: It is the Goyim that we are among them. They are people of Sheker and deceit.
3.
Malbim: They are people who say lies and slander not in front of their victim.
2)
What is "Lashon Remiyah"?
1.
Malbim: He speaks with guile in front of him. He appears to love him, and internally he sets his ambush.