It sounds like you might be dealing with a communication disorder, and there are a few potential explanations for the difficulties you're facing:
Stuttering: Stuttering is a speech disorder characterized by interruptions in the flow of speech. People who stutter may repeat sounds or syllables, prolong sounds, or experience blocks where they are unable to produce a word. Stuttering can worsen when a person is anxious or stressed, as you mentioned.
Selective Mutism: This is a social anxiety disorder where individuals have difficulty speaking in specific social situations, even though they are capable of speaking in other settings. It can be associated with avoiding certain sounds or words.
Articulation Disorder: This occurs when a person has difficulty physically producing certain sounds or letters, like 'K', due to problems with the coordination of the speech muscles.
Word-Finding Difficulty: This is a language disorder where individuals have trouble retrieving the correct words from their memory, which can lead to hesitations and difficulty expressing themselves.
Anxiety and Stress: Both anxiety and stress can significantly impact speech fluency. When anxious or stressed, people might experience muscle tension and mental blocks, leading to difficulty speaking.
It's important to understand that pinpointing the exact cause of your difficulties would require a thorough evaluation by a licensed speech-language pathologist and possibly other relevant healthcare professionals. They can assess your speech patterns, identify any underlying disorders or challenges, and provide appropriate strategies for managing or improving your communication.
If this issue is significantly impacting your daily life and causing distress, I would strongly encourage you to seek professional help from a speech-language pathologist or a mental health professional who can assist you in identifying and addressing the specific issues you are facing. They can provide personalized techniques and therapies to help you improve your speech fluency and manage any anxiety-related challenges.