Appeared to be joined in speech (6)
I believe the answer is:
seemed
'appeared' is the definition.
('seem' can be a synonym of 'appear')
'be joined in speech' is the wordplay.
'be' becomes 'seem' (seeming is a kind of being).
'joined in speech' becomes 'ed' (I can't explain this - if you can you should believe this answer much more).
'seem'+'ed'='SEEMED'
'to' is the link.
Can you help me to learn more?
(Other definitions for seemed that I've seen before include "Appeared, looked" , "Was appearing" , "'Appeared, gave the impression (6)'" .)