S5 texting freezing issue

[AC Question]

I'm constantly having problems with my texting / keyboard app on my S5. Regardless of which keyboard app I use. I wish to type a message I.e. "the weather is nice today" and instead the phone seizes up, and starts repeating words as I continue to hit buttons during the freeze. The text will then appear as "the the weather the weather is the weather is nice" and there is seemingly nothing I can do about it. I teXT fast and often so this is a major headache. I've cleared the cache. Ive maintained very low app usage. What causes this issue?? I had the same problem on my S3. Please advise.