Brief Answer:
Read below.

Detailed Answer:
I read your question carefully and I understand your concern.

What you describe may indicate the first stages of a speech issue like aphasia. Aphasia may be due to brain lesions like stroke or in the setting of cognitive impairment like in dementia. However because at times factors like anxiety are at play, the first step is to have a neuropsychological evaluation, sort of questionnaires which can be administered by your doctor or a trained neuropsychologist, to test language and other higher mental functions, to have a more objective evaluation of language functions.
Only if neuropsychological tests confirm there is indeed a language or other cognitive areas dysfunction then further investigations are needed. Usually with imaging to exclude lesions such as stroke or brain tumor and some blood tests for correctable metabolic causes.

I remain at your disposal for other questions.

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