I also have that problem here. I can't initiate dialogue with any NPC, companion or not. Not even Dogmeat. All I have is a stare contest of "meh" faces, if it's a quest completion dialogue. If I keep pressing "E" when talking to a settler or a companion, all I have access to is trading items. I've got no voices, not even Marcy Long, no barks.
I tried LOTS, and LOTS of "solutions". Verifying cache, disabling mods one by one, always reverting to an older save, tried another character, modifying Fallout4.ini file, new game... Nothing happened.
Right now I'm downloading another language package, while going without a single mod folder in the root. If it does something, I'll update. If not, any help will be welcomed.
EDIT : changing the language pack did brought back dialogues and voices. Now I'll try to reinstall mods, one by one, see wich kind messes up the game; if it does, I'll try a simple language pack change.
Edited by MaitreRakoun, 15 June 2017 - 12:38 AM.