1)
Why should his tongue stick to his palate?
1.
Radak: I should not be able to speak or sing.
2.
Malbim: All my speech is about you (Yerushalayim). If I will not speak about remembrance of you, I will be like a mute, whose tongue sticks to his palate.
2)
What do we learn from "Al Rosh Simchasi"?
1.
Bava Basra 60b: This is [the custom to put] ashes on the head of Chasanim.
2.
Rashi: I will put remember to mourn its Churban at the peak of all my Simchah.
3.
Malbim: This is not only when I am exiled. Also, if I will not put Yerushalayim above the peak of my Simchah, also if I rejoice in worldly success, Yerushalayim will be higher. All Simchah will turn to sadness via recalling its Churban.
