When I was studying Latin, I would learn the conjugation of each verb by memorizing its principal parts (for example, "amo, amare, amavi, amatus"). In Spanish, are there any principal parts of a verb that can be memorized in order to conjugate every form of a regular verb? According to this Yahoo Answers post (which clearly isn't a reliable source), the principal parts of a Spanish verb correspond directly to those in Latin, but I'm not sure if this correct. Do Spanish verbs have principal parts that can be used to conjugate them, like Latin verbs?
All regular verbs are divided in three conjugations: 1st conjugation or -ar verbs, 2nd conjugation or -er verbs, and 3rd conjugation or -ir verbs. (Although 2nd and 3rd are almost identical).
There are three non-finite forms: the infinitive, the past participle and the gerund.
There are four moods: indicative, subjunctive, imperative and conditional. The indicative have four simple tenses (present, imperfect, past and future) and four composite tenses (perfect, plusperfect, anterior and perfect future) althoug I will skip composite tenses as they are formed by conjugating auxiliary verb haber with the past participle. The subjunctive have three simple tenses: present, past (with two forms) and future. The imperative and the conditional have a unique simple tense each.
Let's begin with caminar as an example of a regular 1st conjugation verb.
Infinitive: caminar Participle: caminado Gerund: caminando Infinitive mood Person present imperfect past future s. 1st yo camino caminaba caminé caminaré s. 2nd tú caminas caminabas caminaste caminarás s. 3rd él camina caminaba caminó caminará p. 1st nosotros caminamos caminábamos caminamos caminaremos p. 2nd vosotros camináis caminabais caminasteis caminaréis p. 3rd ellos caminan caminaban caminaron caminarán Subjunctive mood Person present past (-ara) past (-ase) future s. 1st yo camine caminara caminase caminare s. 2nd tú camines caminaras caminases caminares s. 3rd él camine caminara caminase caminare p. 1st nosotros caminemos camináramos caminásemos camináremos p. 2nd vosotros caminéis caminarais caminaseis caminareis p. 3rd ellos caminen caminaran caminasen caminaren Person Conditional Imperative s. 1st yo caminaría s. 2nd tú caminarías camina s. 3rd él caminaría (camine) p. 1st nosotros caminaríamos (caminemos) p. 2nd vosotros caminaríais caminad p. 3rd ellos caminarían (caminen)
The first thing we can notice is thar there are a few patterns. There are two main unstressed conjugations: -a, -as, -a, -amos, -ais, -an which is common in the imperfect (after -àb-), past subjunctive (after -àr-) and conditional (after -arí-); and the -e, -es, -e, -emos, -eis, -en which is common in the subjunctives past (after -às-) and future (after -àr-).
There is one stressed them in the future: -é, -ás, -á, -èmos, -éis, -án. The present subjunctive is almost identical to the unstressed -e- theme, except that first and second plurals are stressed, and the present indicative is similar to the unstressed -a- theme, except for stress in first and second plural and the first singular taking an ending in -o.
A more irregular pattern is found in the past (but if you go to Spain you can forget about this past (or indefinite preterit) as they use almost exclusively perfect preterit). This past theme is -é, -àste, -ó, -àmos, -àsteis, -àron. (I've been using the grave accent ` to mark an unmarked stress).
When we take a second conjugation regular verb as beber we have:
Infinitive: beber Participle: bebido Gerund: bebiendo Infinitive mood Person present imperfect past future s. 1st yo bebo bebía bebí beberé s. 2nd tú bebes bebías bebiste beberás s. 3rd él bebe bebía bebió beberá p. 1st nosotros bebemos bebíamos bebimos beberemos p. 2nd vosotros bebéis bebíais bebisteis beberéis p. 3rd ellos beben bebían bebieron beberán Subjunctive mood Person present past (-ara) past (-ase) future s. 1st yo beba bebiera bebiese bebiere s. 2nd tú bebas bebieras bebieses bebieres s. 3rd él beba bebiera bebiese bebiere p. 1st nosotros bebamos bebiéramos bebiésemos bebiéremos p. 2nd vosotros bebáis bebierais caminieseis bebiereis p. 3rd ellos beban bebieran bebiesen bebieren Person Conditional Imperative s. 1st yo bebería s. 2nd tú beberías bebe s. 3rd él bebería (beba) p. 1st nosotros beberíamos (bebamos) p. 2nd vosotros beberíais bebed p. 3rd ellos beberían (beban)
So, in all past and future tenses we have the same pattern than first conjugation except in the sub-root: past indicative uses -í- instead of -àb-, and the past and future conjunctive using -ièr-, -iès-, instead of -àr-, -às-. The conditional and future indicative are based on the infinitive and therefore use -er- instead of -ar-.
The main difference is that the present indicative and present subjunctive shift cases (but first singular person in the indicative keeps the -o ending), and the simple past (indefinite preterit) has a complete different theme: -í, -ìste, -ió, -ìmos, -ìsteis, -ièron.
The third conjugation is very similar to the second so I will not write it down. Future indicative and conditional use the _-ir- infinitive, and the present indicative first and second person plural in the present indicative are respectively vivimos and vivís, as opposed to bebemos and bebéis.
The imperative mood. I marked in parenthesis the first person plural, and the third persons as they are just the present subjunctive, but they are important as the third person conjugation is used for the formal second person usted and ustedes, and I completely ignored the voseo second person as used in several places in Latin America with different degrees of acceptance.
The second person singular imperative is just equivalent to the second person singular present indicative without the final -s (or equal to third person singular present indicative).
The second person plural imperative is equivalent to change the final -r in the infinitive to a -d.
So you can learn by heart all these cases, or you can learn the patterns.
Now the tricky part: the irregular verbs.
One of the most common irregularities come from verbs inherited from Latin when they had an open
So a verb like tender, the root is tend- when unstressed and tiènd when stressed. Otherwise it is regular, so remember when the conjugation is stressed (as all conjugations with a subroot) or unstressed.
A few verbs are almost regular, but have some consonant shift in the root. For example crecer, with the root crec- (with -c- having a /z/ sound) will shift the /z/ to /zc/ when followed by an open vowel. This affect the first person singular in the present indicative crezco and the whole present subjunctive theme.
Other irregular verbs have phonetically induced changes, particularly when the root ends in a palatalized (or historically palatalized) consonant, such as -ch-. Then all roots with a week diphthong -i- will lose it: plañir → plañendo.
Another common irregularity comes in the future indicative and conditional when the indicative vowel is lost: haber → habrá, tener → tendrá (note consonant added), saber → sabrá, etc.
Then there are two root-changing paradigms. The past tense changing root, and the present tense changing root.
The past tense changing root paradigm are some irregular verbs whose simple past tense, as well as the past and future subjunctive, has a different root. Examples are ir, ser (which are too irregular), estar, caber, poner, tener. The simple past tense (indicative) of these verbs are, respectively:
These are also the roots for the past and future subjunctives: fuera, estuviera, cupiera, pusiera, tuviera.
The present tense changing root paradigm, affect the root in the present tense (indicative and subjunctive) whenever it follows an open vowel. This is similar to the cases when there is a consonant shift (v.g. crecer → crezco), but with a change that goes deeper than the final consonant in the root. This is why I don't include poner an tener as present tense changing root paradigm, as there is only a -n-→**-ng-** consonant shift. But caber is included:
For each verb: all regular verbs and most irregular verbs, if you have the third person conjugation you will be able derive most other conjugations: as some tenses are derived from others, we don't need all ten combinations of mood-tense. We need: all indicative forms and present subjunctive, plus the non-finite forms.
So regular verbs are:
Some slightly irregular verbs include:
Some root changing verbs include:
And complete irregular verbs (some of them with monosyllabic infinitive)
So, knowing these forms you can get most of the forms for both regular an irregular verbs. I hope this is what you mean by principal parts.
A few verbs have a different forms for the participle when used as adjective and as verb in composite tenses (althogh sometimes the difference blurs) such as imprimir with impreso and imprimido; or teñir with tinto and teñido. So from the Latin principal forms I rather prefer the third person singular paradigm, and I add a few more tenses to show main shifts in common irregularities.
Spanish regular verbs have -ar, -er or -ir endings. If you drop those endings, you get a "principal" part or "stem" that you can conjugate.
Some of these principal parts change the stem in certain conjugate forms. For instance, tener has ten-go and ten-emos in the first person forms, but the stem changes to tien-es, tien-e and tien-en in the second and third person forms (the second person plural is teneis, and retains its stem).
Well, conjugations change depending on the category of the verb (AR, ER, IR verbs).
This is an example for the present tense:
However, there are irregular verbs!
To handle every single non-defective verb except for ser, ir, and haber (they have tenses with unpredictably arbitrary conjugations), you could figure out all conjugations with the following principal parts.
So, for a few examples (all irregular in some way)
This even covers odd ball verbs like cernir and adquirir because you can see they stem-change in the present, but not the preterite (thus indicating a lack in subjunctive too).
Most verbs, however, are not very irregular. As noted above, if you're willing to memorize that saber has the odd sé/sabe/sepa and dar/estar just do vowel swap for subjunctive (rather than building off of the yo), then you can entirely remove the present subjunctive conjugation. Ditto for if you're willing to remember the handful of irregular tú commands. But then again, excepting stem changes, you're only ever looking at a dozen irregulars in each tense, so honestly, you're better off just learning them.
If you really want to, though, I'd recommend just sticking with, for example with tener: tengo, tiene, tuvieron. Those are the forms whose irregularities will most heavily propogate in other conjugations, giving you nearly 95+% coverage and leaving you with just future and tú commands to memorize separately which are quite painless.