Aorist Tense:

Simple fact.
Once and for all.
ἐθέλω μαθεῖν τὴν ἑλληνικὴν γλῶτταν.
I want to learn Greek, meaning: learn it so as to know it.
Unless of course you want to say: I want to be busy with that study.
What do you want to do (=be doing) this afternoon? - Oh, I intend to do some Greek studying
   ἐν νῷ ἔχω μανθάνειν τὴν ἑλληνικὴν γλῶτταν.

  Aorist Infinitive Forms  
      NO past tense marker 
 μαθ      2nd aorist stem 
    εῖν     active infinitive marker  
      NO past tense marker 
 γεν      2nd aorist stem 
    έσθαι     middle infinitive marker  

τί βούλει ποιεῖν;  
  βούλομαι μανθάνειν 
I want to study
τί βούλει μανθάνειν;  
    βούλομαι μανθάνειν τὸ ἐνδέκατο μάθημα 
I want to study lesson 11 (=spend some time on it)
διὰ τί;  
    βούλομαι καταλαβέσθαι τὸν ἀόριστον I want to understand the aorist (once and for all)
We say under-stand, the Greeks say: down-grab/seize
Remember: (seizes, grabs hold of)
    ὁ Ὀδυσσεὺς λαμβάνεται τῆς τοῦ Μινωταύρου κεφαλῆς.