My cat can't meow anymore? Is something seriously wrong?

We move up to our summer home every May and of course we bring my 11 year old cat, Bitty, up with us. About a day or two after the move this year, I noticed that her meow was rather hoarse and now it doesn't make a sound at all. She is long haired, so at first I assumed maybe she just had another hairball but it's been two weeks and there hasn't been any change at all in her voice, her behavior has remained totally normal though, she seems slightly less hungry but not at an alarming level. The house we are at is at a much higher altitude but I didn't think that would affect it. There are several locust trees on our property so could it maybe be allergies? or even a cold? or should I just go take her to the vet just to be safe?