JLanguage said:
It's hard to remember all those different endings.
Usually the only time a Spanish noun changes its ending is when you pluralise it. Otherwise, they tend to end in -o, or -a, or something else. But you only have to learn one form and a couple of rules about how to make them plural.
The endings for Spanish verbs are much more regular than in any other language I've studied. The future-tense and conditional-tense endings are the same for all but a handful of verbs. For other tenses, almost all verbs follow one of two 'tracks': verbs that end in -ar and verbs that don't. The endings for each 'track' are regular for every verb, although there are a handful of them (mostly the same handful as for future and conditional) that are different. The endings for person (I, you, he/she/it, etc) follow very regular patterns; the preterite is the only tense for which you have to learn a different set of endings for each person. Many verbs undergo stem changes when the stem is stressed rather than the ending, but these also follow very regular rules. In my opinion, you can learn how to conjugate pretty much any verb in just a few hours of reading/listening and practice.
The grammar takes time to learn, but I don't think it's any worse than for any other Romance language; in fact, the flexibility of the word order makes it easier. The things that take a while to learn are idiom, metaphor, proverbs, and so on. But then that's true of any language.