My cat has lost her meow

I have a female cat who is just over one year old. We moved to a farm in November 2014 and the female farm cat there had kittens in the barn, we've been around them since 4weeks old and tigger (cat in question) has always been very vocal. Her mother died a couple of months ago and she has been even more vocal since but in the past few days her voice has pretty much disappeared. She has been trying to call but at first it was just squeaks and croaks but now her mouth just opens and nothing comes out. Can anyone give me an indication of what could be wrong? Thank you in advance.

If she's been meowing incessantly, she could have lost her voice like a person would after yelling at a football game all afternoon.

Otherwise some other causes could be a URI, laryngeal paralysis (she would start having problems eating/drinking too), or a growth in her throat.