Remember, after verbs like 'look', 'feel', 'sound', 'smell' and 'taste', we use adjectives not adverbs:
Anna looks good in that new dress.
(= She has a good appearance.)
'well' is usually an adverb but sometimes it's an adjective which means 'healthy':
The cat doesn’t look well.
(= It doesn’t look healthy, it looks ill.)
Exercise
Hello niloofar 64,
Both sentences are correct and can be used interchangeably. 'Good' is an adjective and describes the noun 'English', which 'well' is an adverb and describes the verb 'speak'.
Peter
The LearnEnglish Team
Hello musashow17,
It's hard for me to comment on this as I would need to hear the actual speech in order to judge if the interjections are confusing, irritating, too frequent and so on, but in general there is nothing wrong with using sound such as these. Many native speakers use sounds like 'mmm' when they need to hesitate but want to signal that they have not finished speaking.
Peter
The LearnEnglish Team