Just like in English, sentences in Spanish usually contain a verb. Verbs can be used to describe an action, a feeling or to describe something that is happening. In Spanish, verbs need to be ...
This means changing the verb into a different form. In Spanish, it isn't usually necessary to use the subject pronoun (I/you/he/she/it etc). The verb ending makes it clear who is doing the action.
Spanish, on the other hand ... Languages with non-Roman alphabets, like Arabic, Thai, or Farsi, generally run into the same space issues as a language with the Roman alphabet would.