Interesting question; I learned something in answering it! I'd never heard the word scattershot specifically; I guessed from context that it was similar to (if not exactly like) a "fair-weather friend"; someone who's there only part of the time, depending upon how easy/difficult it is to be a supportive friend at the time. Google defines scattershot:
denoting something that is broad but random and haphazard in its range.
Dictionary.com provided some interesting insight. First, the definition:
scattershot, adjective
- random; haphazard: their approach to conservation is scattershot and unscientific
And now for the interesting part, found further down the page in the Word Origin and History section...
adj. 1959, figurative use of term for a kind of gun charge meant to broadcast the pellets when fired (1940), from scatter (v.) + shot (n.).
For me, at least, this made the word make much more sense. The word scattershot would therefore be akin to "hit-and-miss", which also has origins in weaponry; you take a shot, and sometimes you get a hit and sometimes you don't, and you're never really sure if or when/where a pellet is going to make contact.
Figuratively, in our scattershot friend example, we replace "pellet" with "efforts at acting like a friend"; the speaker never knew if or when he could count on his friend, so rather than terming him "a reliable friend" or "an absentee friend", he struck the middle ground: "a scattershot friend", who may or may not be there when I need him.
Best Answer
Nice question. You actually ask if the auxiliary verb (am) refers to the word "busy" or to the word "learning". I think that you asked this question because you assume that if it refers to the word "busy" then the word "learning" is a gerund, and if it refers to the word "learning" then the word learning is a verb in present participle tense.
I guess that it's not simple to answer on it since not any case in English has rule, but personally I believe it depends on the context and meaning of the phrase. That says, that if you say your phrase in following meaning:
then in this meaning the word "learning" is gerund, since it functions the same as if was written: "I'm busy in learning English".
But if you say your phrase in this meaning:
Then, it's as if was written "I'm busy now because I'm learning English" since there is a using of pronoun + auxiliary verb in this sentence (I am...), near to the word which ends with -ing ending, therefore it is a verb that functions as present participle.
It cannot be a gerund, since the definition of gerund is "form of a verb which acts as a noun". In your case it does not acts as a noun because of the presence of the pronoun (I) with the auxiliary verb (am) right before the word ends with -ing.
If you wrote "Learning English makes me busy", or "Learning English is easy" then the word "learning" would be a gerund in both of these sentences because they are themselves the 'instead of' the pronoun, the subject of the sentence rather than additional to it.
BTW, I found similar question in this forum and you can see another opinions.