lasst part of person's last name is missing after install ing os 10 yosemite and using alva bc 640

Hello to all I am trying to help some one who has a alva bc 640 and her problem is when ever she writes a person's last name the last part of the last name is missing.
She is using a mac with os 10 yosemite and she is using a alva bc 640.
Here is a little more discription of the problem below.
Hi, all. I have a n Alva bc640 from Optelech. Ever since I installed Yosemite I’ve had an issue in which the last part of a person’s last name is missing. For example if Isaac Hebert writes in I see “Isaac H” but the voice says his full name. The rest of the text is normal. Anyone else had this issue