Questions & Answers about Усталый человек хочет спать.
Why is спать in its dictionary form (infinitive) instead of being conjugated?
Just like in English ("wants to sleep"), when you have a conjugated verb expressing a desire like хочет (wants), the action verb that immediately follows it stays in its infinitive form. You only change the ending of the first verb.
Why does the adjective усталый end in -ый?
In Russian, adjectives must match the noun they describe. Because человек (person) is a masculine, singular noun and is the subject of the sentence (nominative case), the adjective takes the standard masculine singular ending -ый.
I learned that the verb "to want" is хотеть. Why does it look like хочет here?
Хотеть is a very common but slightly irregular verb. For singular subjects, it takes the standard -е- conjugation endings, making "he/it wants" хочет. Since our subject is человек (a third-person singular noun), we use this form.
How come there is no word for "a" before усталый человек?
Russian does not have definite or indefinite articles (the words "a", "an", or "the"). Depending entirely on the context, усталый человек translates to either "a tired person" or "the tired person".