Good questions.
Most languages are synthetic, which means that the way words are arranged to create sentences (syntactic relationship) rely heavily on inflections (particles added to express a grammatical function) or agglutinations.
For example, verbal tenses, number (plural or singular), person (first/I/, second /you/, third /he, she/), etc.
In Spanish, an inflection on the verb is enough to know who is the subject:
escribo (I write), escribes (you write), escriben (they write), escribimos (we write), escribe (s/he writes).
In the case of verbal tense:
Compare
yo como (I eat), yo comí (I ate), yo comeré (I'll eat) in Spanish, an inflection, a particle added to the end of the word marks the verbal tense.
In some cases, the inflection added is derivational, that is, itchanges the grammatical category of the word (sing /verb/...singer /noun/). --er is one of the many bound morphemes in English; it does not mean much alone, but added to another morpheme...
In spanish we have cantar (to sing), cantante (singer); so ...nte would be the bound morpheme that helps create new grammatical categories.

The opposite of synthetic languages would be analytical or isolating languages (such as Chinese or Vietnamese), which rely more on separate word, articles or prepositions to create the syntactic relationships. Modern English has become more analytic, but shares features of both categories.

As for the downvoting issue, we have been told it has nothing to do with the actual content of the post, which makes it more unfair, and that we should not be worried about it. It is a worrying matter nonetheless. Hopefully it will stop. I am just trying to create good content here.