Now English is very limited in what it can "squish together" into a simple verb form. We can add -s to mean "he/she form, present tense" (sleep > sleeps); we can add -ed or use a special form to mean "past tense" (walk > walked; steal > stole). But that's more or less it for simple forms in English. If we want to form other tenses in English, we have to make a compound form consisting of several words: was walking, will sleep, would see. And notice that in English, endings aren't generally added for different persons: while -s on the end of a verb matches a "he/she" subject, there is no corresponding ending for we or they.
Spanish, like other related languages such as French, has many more possibilities in its simple forms. In general, a Spanish verb packs all of the following into a single word form:
verb stem + tense marker + person marker
For example, the form veíamos is from the Spanish verb ver, meaning to see, watch. The form veíamos normally means something like "we were watching" (as in we were watching TV), and can be broken down into the following parts:
In contrast with English's simple present/past distinction, Spanish has no fewer than seven different tenses that can be formed in a single word2.
The above formula of stem + tense + person makes things look simpler than they actually are. In many verb forms, there are complications in how these parts are actually put together. For one thing, some verbs have irregular stems, which in turn can depend on the tense. So in that sense, the "stem" and "tense" part of the verb form aren't quite so separate all the time. And although the ending -mos works for all forms, other persons such as the I form, can actually have different endings depending on the tense. So the "tense" and "person ending" parts of the verb form aren't always quite so separate either.
Getting started with Spanish verbs: the present tense
The first tense that beginners usually learn is the (simple) present tense. On the next page, we look at the present tense of regular -ar verbs.
1. The imperfect tense generally carries the notion of "non-delimited action in the past",
often translated by was/were ...ing, or used to ... in English.
Some authors actually analyse this in terms of both "tense" (past) and "aspect"
(non-delimited), but that's not important for us here.