Why is it written v'Ayev, and we pronounce it v'Aye?
Radak: Where 1 is the matter that you trusted in from the mouth of your Nevi'im?
Chomas Anach: There are various kevels of Nevu'ah; v'Ayo 2 hints to the highest level, and v'Ayeh to other levels. (Where are they? We see that they are false Nevi'im!)
According to this, Radak does not explain why the Kesiv and Kri are different. He wrote elsewhere (refer to Shmuel II, 15:21:1:1) that Chachamim decided that when there are discrepancies among texts, the pronunciation will follow the majority text, and it will be written like the minority text. Here, some texts of Radak say that it is written 'v'Ein', but I did not see any texts of Yirmeyah that say so. (PF)
Elsewhere in Tanach (e.g. Shemos 2:20), it is pronounced Ayo. Here, printed texts imply that according to the Kesiv, it should be v'Ayev. (PF)
