1)
What is the meaning of "Nimletzu"?
1.
Rashi: They were sweet. Radak - this is a metaphor for perfection of speech. Divrei Torah are compared to honey, for its words are sweet.
2.
Malbim: It is an expression of Melitzah (metaphor or parable).
2)
Why does it say "l'Chiki"?
1.
Malbim: 'Tasting' Imrasecha is intellectual discernment. I find there a dear Melitzah and elevated Dibur. Under the Torah's stories are deep parables and grand matters.
3)
Why does it say "Nimletzu" (plural) and "Imrasecha" (singular)?