alterar — Spanish conjugation
to alter, to change
Indicative
Present (Presente) Regular
The present tense is the most versatile tense in Spanish. It covers actions happening right now, habitual actions, and even near-future plans. One form does the work of three English constructions.
Ella habla inglés — She speaks / is speaking English
| Pronoun | Spanish | English |
|---|---|---|
| yo | altero | I alter |
| tú | alteras | you alter |
| vos | alterás | you alter |
| él/ella/Ud. | altera | he/she/it alters |
| nosotros | alteramos | we alter |
| vosotros | alteráis | you (pl.) alter |
| ellos/ellas/Uds. | alteran | they alter |
Preterite (Pretérito indefinido) Regular
Used for completed past actions with a defined endpoint — a single event, a series of events, or an action that interrupted another. Common with time expressions like ayer, el lunes, una vez.
Ella habló de ti ayer — She spoke about you yesterday
| Pronoun | Spanish | English |
|---|---|---|
| yo | alteré | I altered |
| tú | alteraste | you altered |
| vos | alteraste | you altered |
| él/ella/Ud. | alteró | he/she/it altered |
| nosotros | alteramos | we altered |
| vosotros | alterasteis | you (pl.) altered |
| ellos/ellas/Uds. | alteraron | they altered |
Imperfect (Pretérito imperfecto) Regular
Describes ongoing or habitual past states — what things were like, background context, what used to happen. Contrasts with the preterite which marks completed events.
Cuando era niño vivía en Valencia — When I was a child I lived in Valencia
| Pronoun | Spanish |
|---|---|
| yo | alteraba |
| tú | alterabas |
| vos | alterabas |
| él/ella/Ud. | alteraba |
| nosotros | alterábamos |
| vosotros | alterabais |
| ellos/ellas/Uds. | alteraban |
Conditional (Condicional) Regular
Expresses hypothetical actions, polite requests, and what would happen under certain conditions. Also used for reported speech about the future from a past perspective.
¿Podrías ayudarme? — Could you help me?
| Pronoun | Spanish | English |
|---|---|---|
| yo | alteraría | I would alter |
| tú | alterarías | you would alter |
| vos | alterarías | you would alter |
| él/ella/Ud. | alteraría | he/she/it would alter |
| nosotros | alteraríamos | we would alter |
| vosotros | alteraríais | you (pl.) would alter |
| ellos/ellas/Uds. | alterarían | they would alter |
Future (Futuro) Regular
Expresses future actions, predictions, and probability about the present. Formed with the full infinitive as stem for most verbs. In spoken Spanish, ir a + infinitive is often preferred for near future.
Ella hablará en conferencia mañana — She will speak at the conference tomorrow
| Pronoun | Spanish | English |
|---|---|---|
| yo | alteraré | I will alter |
| tú | alterarás | you will alter |
| vos | alterarás | you will alter |
| él/ella/Ud. | alterará | he/she/it will alter |
| nosotros | alteraremos | we will alter |
| vosotros | alteraréis | you (pl.) will alter |
| ellos/ellas/Uds. | alterarán | they will alter |
Present perfect (Pretérito perfecto) Regular
A compound past tense linking a past action to the present moment — something that has happened and still feels recent or relevant. More common in Spain than Latin America where preterite is preferred.
Hoy he hablado con el jefe — Today I have spoken with the boss
| Pronoun | Spanish | English |
|---|---|---|
| yo | he alterado | I have altered |
| tú | has alterado | you have altered |
| vos | has alterado | you have altered |
| él/ella/Ud. | ha alterado | he/she/it has altered |
| nosotros | hemos alterado | we have altered |
| vosotros | habéis alterado | you (pl.) have altered |
| ellos/ellas/Uds. | han alterado | they have altered |
Pluperfect (Pretérito pluscuamperfecto) Regular
The past of the past — describes an action that was already completed before another past event happened. Always implies a reference point in the past.
Ya había hablado cuando llegaste — She had already spoken when you arrived
| Pronoun | Spanish | English |
|---|---|---|
| yo | había alterado | I had altered |
| tú | habías alterado | you had altered |
| vos | habías alterado | you had altered |
| él/ella/Ud. | había alterado | he/she/it had altered |
| nosotros | habíamos alterado | we had altered |
| vosotros | habíais alterado | you (pl.) had altered |
| ellos/ellas/Uds. | habían alterado | they had altered |
Conditional perfect (Condicional perfecto) Regular
Expresses what would have happened — actions that were possible but did not occur, or regrets about the past. Formed with conditional of haber + past participle.
Habría hablado, pero no me dejaron — I would have spoken, but they did not let me
| Pronoun | Spanish |
|---|---|
| yo | habría alterado |
| tú | habrías alterado |
| vos | habrías alterado |
| él/ella/Ud. | habría alterado |
| nosotros | habríamos alterado |
| vosotros | habríais alterado |
| ellos/ellas/Uds. | habrían alterado |
Future perfect (Futuro perfecto) Regular
Describes an action that will have been completed by a certain point in the future, or expresses probability about a recent past action.
Para el lunes habré terminado — By Monday I will have finished
| Pronoun | Spanish | English |
|---|---|---|
| yo | habré alterado | I will have altered |
| tú | habrás alterado | you will have altered |
| vos | habrás alterado | you will have altered |
| él/ella/Ud. | habrá alterado | he/she/it will have altered |
| nosotros | habremos alterado | we will have altered |
| vosotros | habréis alterado | you (pl.) will have altered |
| ellos/ellas/Uds. | habrán alterado | they will have altered |
Subjunctive
Present subjunctive (Subjuntivo presente) Regular
Used in subordinate clauses after expressions of desire, doubt, emotion, necessity, or impersonal statements. Triggered by a change of subject between the main and subordinate clause.
Espero que hable — I hope she speaks
| Pronoun | Spanish |
|---|---|
| yo | altere |
| tú | alteres |
| vos | alteres |
| él/ella/Ud. | altere |
| nosotros | alteremos |
| vosotros | alteréis |
| ellos/ellas/Uds. | alteren |
Imperfect subjunctive (-ra) (Subjuntivo imperfecto (-ra)) Regular
The past subjunctive used after past main verbs, in if-clauses with conditional, and for polite softening. The -ra form is more common in everyday speech than the -se form.
Si pudiera, lo haría — If I could, I would do it
| Pronoun | Spanish |
|---|---|
| yo | alterara |
| tú | alteraras |
| vos | alteraras |
| él/ella/Ud. | alterara |
| nosotros | alteráramos |
| vosotros | alterarais |
| ellos/ellas/Uds. | alteraran |
Imperfect subjunctive (-se) (Subjuntivo imperfecto (-se)) Regular
The alternative past subjunctive form. Interchangeable with -ra in most contexts but slightly more literary or formal. Both forms are grammatically correct in all regions.
Si pudiese, lo haría — If I could, I would do it
| Pronoun | Spanish |
|---|---|
| yo | alterase |
| tú | alterases |
| vos | alterases |
| él/ella/Ud. | alterase |
| nosotros | alterásemos |
| vosotros | alteraseis |
| ellos/ellas/Uds. | alterasen |
Perfect subjunctive (Pretérito perfecto de subjuntivo) Regular
A compound subjunctive that expresses completed actions in a subjunctive context — used after present or future main verbs expressing doubt, emotion or desire.
Dudo que ya haya llegado — I doubt she has already arrived
| Pronoun | Spanish |
|---|---|
| yo | haya alterado |
| tú | hayas alterado |
| vos | hayas alterado |
| él/ella/Ud. | haya alterado |
| nosotros | hayamos alterado |
| vosotros | hayáis alterado |
| ellos/ellas/Uds. | hayan alterado |
Pluperfect subjunctive (Pluscuamperfecto de subjuntivo) Regular
Expresses what had happened in hypothetical or unreal past contexts — the subjunctive equivalent of the pluperfect. Common in contrary-to-fact past conditions.
Si hubiera hablado, lo habrían creído — If she had spoken, they would have believed her
| Pronoun | Spanish |
|---|---|
| yo | hubiera alterado |
| tú | hubieras alterado |
| vos | hubieras alterado |
| él/ella/Ud. | hubiera alterado |
| nosotros | hubiéramos alterado |
| vosotros | hubierais alterado |
| ellos/ellas/Uds. | hubieran alterado |
Other forms
Imperative (affirmative) (Imperativo afirmativo) Regular
Direct commands and instructions. The imperative only exists for tú, usted, nosotros, vosotros and ustedes — yo has no command form. Affirmative and negative forms use different conjugations.
Habla más despacio — Speak more slowly
| Pronoun | Spanish |
|---|---|
| tú | altera |
| vos | alterá |
| él/ella/Ud. | altere |
| nosotros | alteremos |
| vosotros | alterad |
| ustedes | alteren |
Imperative (negative) (Imperativo negativo) Regular
Negative commands use the subjunctive forms for all persons. Formed with no + present subjunctive. This applies to all persons including tú where the affirmative uses a different form.
No hables tan rápido — Do not speak so fast
| Pronoun | Spanish |
|---|---|
| tú | no alteres |
| vos | no alteres |
| él/ella/Ud. | no altere |
| nosotros | no alteremos |
| vosotros | no alteréis |
| ustedes | no alteren |
Present progressive (Presente progresivo) Regular
Emphasises that an action is happening right now at this very moment. Less common than in English since the present tense already covers ongoing actions in Spanish.
Estoy hablando contigo — I am speaking with you
| Pronoun | Spanish |
|---|---|
| yo | estoy alterando |
| tú | estás alterando |
| vos | estás alterando |
| él/ella/Ud. | está alterando |
| nosotros | estamos alterando |
| vosotros | estáis alterando |
| ellos/ellas/Uds. | están alterando |
Preterite progressive (Pretérito indefinido progresivo) Regular
Describes an action that was in progress throughout a completed past period. Uses the preterite of estar + gerund to emphasise the ongoing nature within a defined timeframe.
Estuvo hablando toda la tarde — He was talking all afternoon
| Pronoun | Spanish |
|---|---|
| yo | estuve alterando |
| tú | estuviste alterando |
| vos | estuviste alterando |
| él/ella/Ud. | estuvo alterando |
| nosotros | estuvimos alterando |
| vosotros | estuvisteis alterando |
| ellos/ellas/Uds. | estuvieron alterando |
Imperfect progressive (Pretérito imperfecto progresivo) Regular
Emphasises an ongoing background action using the imperfect of estar + gerund. Layered on top of the imperfect which already conveys continuity — used for extra emphasis on the progressive nature.
Estaba hablando cuando entró — I was speaking when he came in
| Pronoun | Spanish |
|---|---|
| yo | estaba alterando |
| tú | estabas alterando |
| vos | estabas alterando |
| él/ella/Ud. | estaba alterando |
| nosotros | estábamos alterando |
| vosotros | estabais alterando |
| ellos/ellas/Uds. | estaban alterando |
Conditional progressive (Condicional progresivo) Regular
Expresses what would be in progress under hypothetical conditions. Uses the conditional of estar + gerund. Less common but used for emphasis on the ongoing nature of a hypothetical action.
Estaría hablando ahora si pudiera — I would be speaking now if I could
| Pronoun | Spanish |
|---|---|
| yo | estaría alterando |
| tú | estarías alterando |
| vos | estarías alterando |
| él/ella/Ud. | estaría alterando |
| nosotros | estaríamos alterando |
| vosotros | estaríais alterando |
| ellos/ellas/Uds. | estarían alterando |
Future progressive (Futuro progresivo) Regular
Describes an action that will be in progress at a future point, or expresses probability about an ongoing present action. Uses the future of estar + gerund.
Mañana a esta hora estaré viajando — At this time tomorrow I will be travelling
| Pronoun | Spanish |
|---|---|
| yo | estaré alterando |
| tú | estarás alterando |
| vos | estarás alterando |
| él/ella/Ud. | estará alterando |
| nosotros | estaremos alterando |
| vosotros | estaréis alterando |
| ellos/ellas/Uds. | estarán alterando |