Speak for a long time in hotel, long-standing, overlooking Scottish river (4,5)
I believe the answer is:
hold forth
'speak for a long time' is the definition.
I can't tell whether this definition defines the answer.
'hotel long-standing overlooking scottish river' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'long-standing' becomes 'old' ('old' can be similar in meaning to 'long-standing').
'overlooking' is a charade indicator (letters next to each other) (down clues only).
'scottish river' becomes 'forth' (I've seen this before).
'h'+'old'+'forth'='HOLD FORTH'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for hold forth that I've seen before include "speak in public?" , "lecture" , "Speak at length" , "Present" , "Show how to" .)