How did you learn to do that? Looks great!

The character is "litero".

-j is plural, -n is accusative. Adhectives take the same endings as their nouns much of the time.

It looks like that may be accepted now, however "you write nice letters" is not, even though it is a suggested translation.

I think they count pretty as "beleta", since it's at a lesser degree than beautiful

The Tips & Notes section has this to offer: " Pronunciation

-oj is pronounced like the English oy, and the pronunciation of -aj is like the English eye. "

Since Esperanto is partially based in German, it adopts that pronunciation of the letter "j," at least as far as I've seen, which is to pronounce it as you would a "y." For instance, in German "ja" is pronounced "ya," "jaeger" is "yaeger," and "Junker" is "younker." Hope that helps!

Here's some simple rules to help get it right, and it all depends on the verbs used:

1. If you're saying someone is something e.g. "Ni estas belaj leteroj" (We are beautiful letters) you use only the -j ending because we're stating we are beautiful letters. Imagine estas means equals. So nothing is happening to the belaj leteroj. It's just that we are beautiful letters.

2. If something is happening to something, you use the -jn ending because the -n ending makes it an accusative case. What does that mean? It means something is happening to them. This can be anything e.g. havas (have), amas (love), or skribas (write). So if you say "I have beautiful letters you need to say "Mi havas belajn leterojn" with the -jn ending because something is happening to them.

3. You probably already know, but if something is plural it needs the -j ending.

4. If something is happening to something it needs the -n ending.

I hope that helps and that it makes sense. as well.

"beleta" or the poetic "linda" can be used for "pretty" but "bela" is more common for both.

That would be 'bonajn leterojn" instead of "belajn leterojn"