Kind of like:
- not good at expressing oneself
Kind of like:
Well, "not good at expressing oneself" sounds like "inarticulate." "Not verbose" sounds like "quiet," or perhaps "reticent."
Timid seems like a good option here, since you seen to be indicating that in-person is key.
I think that perhaps taciturn could work even better.
"Tongue-tied" might describe that red-faced, ear-ringing, throbbing jugular panic that accompanies sudden speechlessness in the moment of truth.
I think reticent may give the idea:
Inclined to keep one's thoughts, feelings, and personal affairs to oneself.
There's no single word I can think of.
However, the usual expression is poor verbal communication skills (a mouthful, but that's what it is.)
See Verbal Communication on selfgrowth and Communication Skills on WP.
Cerebrotonic Designating a personality type characterised as intellectual, introverted, and emotionally restrained.
Reserved: formal or self-restrained in manner and relationship; avoiding familiarity or intimacy with others: a quiet, reserved man. 4. characterized by reserve, as the disposition, manner, etc.: reserved comments.
I found a reference once to Alexithymia in a biographical work and was intrigued by the concept. Wikipedia says: "a personality construct characterized by the sub-clinical inability to identify and describe emotions in the self".
After doing some research, it is actually a specific medical term used for clinical diagnosis: A person who might appear as an automaton in both personal and social situations. However, in the biographical work I was reading, it was used much more loosely. For example, men raised in broken families, perhaps in inner-city, survival-of-the-fittest environments, will have trouble later in life showing emotion, forming attachments and expressing love, and the author uses the word "alexithymia" in this context.
Reserved would be a good option when the person chooses to keep her/his thoughts to herself/himself.
Stilted also a possibility:
(Of a manner of talking or writing) stiff and self-conscious or unnatural
wordnetweb.princeton.edu/perl/webwn?s=dyslogia
see the word dyslogia- impaired ability to express ideas verbally.
for inability to express thoughts in written, consider agraphia.
if this doesn't satisfy you then choose the answer voted most.