in English there are no articles that are changed by gender, but in other languages there are different articles that change based on gender, and yes, even objects, i am bilingual, i know English and Spanish, so this is common for me, i'm seeing that articles changed based on gender may be common, it is also present in German. That's a good thing about being bilingual, so keep studying!
Genders generally match the endings quite well. A look at the ending in the dictionary form is usually enough. It works the same for native words and loanwords (for the most part). The simplified system looks like this:
- Nouns ending in -а, -я, -ия, -ья are normally feminine (e.g., мама, земля, роза, гитара, история, физика). Nouns for males will still be masculine (папа, мужчина, дядя, дедушка).
- Consonant-ending nouns are masculine (e.g., жираф, компьютер, стул, рай, волк, гвоздь, планетарий, медведь)
- nouns ending in о/е/ё are neuter (e.g, молоко, море, копьё, утро, окно, яйцо).
- nouns ending in -ь can be feminine or consonant-ending masculine; check the dictionary.
- имя "name", время "time" are in a very small group of neuter nouns with an unusual declension pattern.
- For boy / girl names, the sex of the person is the gender of the name, i.e. Никита is masculine and Саша's gender depends on whether it stands for Alexander or Alexandra.
- Loanwords that violate these patterns are indeclinable
The reality is a bit more nuanced.
Well, Duolingo initially was very eager to have a natural approach with zero grammar, and the user figuring out what is going on. Which, probably, works OK for similar languages but not so great when you cannot understand why a lot of stuff is changing for no apparent reason.
We will likely be able to incorporate some tips in the next version of the tree. Current Russian tips are only available in the desktop version (and they suffer because of the fairly long skills we made back then).
For the most part, a look at the ending in the base form is enough, see above.
Nouns that mean males or females will match the biological sex of the person (i.e. words like папа or мужчина are masculine, and all sorts of foreign girl's names like Эшли, Каэ or Лоис are feminine)
Гитара is feminine. Having a final -а or -я is typical of feminine nouns in Russian. Some masculine nouns are there, too (e.g., мужчина, папа, дядя, дедушка, Миша, Петя) as well as common gender nouns (пьяница, судья) but mostly you'd expect such noun to be feminine.
This is the way loanwords get their gender. Cosonant-ending nouns usually become masculine, whereas nouns ending in -а or -я tend to become feminine. It does not work with people's names, for example— Джилл is a non-declinable feminine noun (meaning, all its forms are the same) because we know it should be a female's name. Интернет, сайт, монитор or фейсбук are all masculine.
Try installing a keyboard layout for Russian. Windows 10 (if you use that system) has a choice betwen the standard Russian layout (ЙЦУКЕН) and the mostly phonetic "Mnemonic" layout (note that some letters are typed as combinations).
You aren't going to a Russian speaking country, are you?