Maybe one of your speech therapists was Irish? I had a Japanese instructor with a British accent when speaking English but he had never left Japan. He had learned English from a British teacher.
One of my daughters had an unusual speech impediment as a child. We never knew why, and she outgrew it, but lots of people asked me why she had a Swedish accent. Even my own dad kept telling me she must be spending a lot of time with somebody from Sweden or she wouldn't talk like that.
