I'm unsure if there's another exchange that would be more appropriate for this, but I'm curious about my own experiences and wanted to see what this community had to say.
Context being that I really enjoy languages and etymology, I have studied French, Japanese, Spanish and the relationships between English, Romantic languages, and by intuitive delta see German influences in modern English.
However, after studying French, Spanish and Japanese I've found that I have more difficulty arriving at the proper phrasing or terminology when speaking English and have occasionally found myself using grammar structures or sentence orders from Japanese, or making similar mistakes I've observed of ESL speakers that natively speak Spanish. Another observation here is that this happens when speaking more frequently than while typing.
My question here is primarily concerned with whether studying the other languages caused this result and if so, why?