@Jo1313 " I could see that but a visually inpaired person wouldn't. "
Is the close captioned option on your TV on? If so, it's probably just a setting on your TV or cable box that is the issue. If in spanish sometimes, you may have the spanish setting set up somewhere on the TV or the cable box and if Spanish isn't available, you are getting English, so that's why the problem isn't all the time. And if closed captioned isn't available on the program, you might not see anything unusual.
I would call them and have someone come check it out. If you are able to get a recording of the issue while it's happening, that is always helpful to show the person who comes to fix it. Not the same issue, but my Dad made a recording and it was helpful to try to show/explain since it was intermittent.
Also, how long has it been since the cable line was installed on your house? Maybe you are getting interference from someone who is using a ham radio or something similar? ...just guessing, but I would call the cable company and have them check it out.
......You look like I need a drink.....