Mandarin, Arabic, Japanese - I would say languages with more complicated characters are harder..
Ajjajajaja huh aksjdjdjdjkxkx
Metabolizing, because it is breaking it down to get it our of the body.
<span>But I have heard the term Oxidation too, because of alcohol oxidation rates. </span>
All of the above, always use extra exclamations and reason for your writing
Make flashcards.
Make catchy songs.
Write them 5 times each.
and so on, hope this helps. :)