Context! If there's no direct object in the sentence giving you a hint on what you drink, you cannot know for sure if you're just drinking, or drinking something that's been mentioned already.
All -ik verbs have that issue in first-person conjugation, but luckily also most -ik verbs are intransitive. :)
Of course, but there is no context in these sentences...so both translations should be accepted. And reporting is a useless action at this point because nothing has been touched in months.
Are most really intransitive? All I can think of now (as I sit here at my desk at work, so not really in a Hungarian mindset), iszik, eszik, jatszik...all can take 'it' as their object...
So, as a rule of thumb, if the verb ends in -ik, the 1st person singular form will end in "-m" and the 2nd person informal singular will end in "-l"; if it ends in something other than "-ik", the 1st person singular form will end in "-ak/ek/ök" and and the 2nd person informal singular will end in "-sz"?
(That was maybe a little too wordy...)
Yes, mostly. There are tables in the notes to skills "Verbs 1: Present Single" and "Verbs 2 Present Plural", though they don't cover -ik verbs. And it gets a bit more complicated because definite conjugation (skill "Definite conjugation" ;-)) adds other forms for the second person.
Not quite -- the "l" and the "m" are independent, I believe.
If the verb ends in -ik, the 1st person singular form will end in -m. (But at least for some Hungarians and some verbs, -k sounds not uneducated but natural.)
If the verb stem (disregarding any -ik) ends in -s -sz -z -dz, the 2nd person informal singular will end in -l.
Here, both rules match (iszik has both -ik and -sz).
And as gergo2 pointed out, endings change again in the definite conjugation....