THE IMPERFECT
The imperfect is the other half of the Spanish past. Where the preterite narrates events, the imperfect describes: what things were like, what used to happen, what was going on. Hablaba can mean “I was speaking”, “I used to speak”, or simply “I spoke, back then”. English needs three phrasings for what Spanish does with one tense.
The regular endings
This is the friendliest set of endings in the language. The -er and -ir classes share one pattern, as in the preterite, and the yo and él forms are identical: hablaba is both “I spoke” and “he spoke”, with context doing the work.
hablar → habl- + …
comer → com-, vivir → viv-
Every -ía ending carries its accent, in every person: comía, comíamos. The -aba set takes one only on nosotros: hablábamos.
Describing, not narrating
Use the imperfect for how things were (background, habit, states, time, age, weather), and the preterite for what happened. A story typically sets its scene in the imperfect and then advances in the preterite.
Cuando era niño, jugaba en la calle.
When I was a child, I used to play in the street. A habit in the past, with era setting the time of life.
Eran las diez y llovía.
It was ten o'clock and it was raining. Time and weather: pure description, so both verbs are imperfect.
Estaba cansado, así que no salí.
I was tired, so I didn't go out. The state is imperfect; the decision (no salí) is a preterite event.
Only three irregular verbs
The imperfect has exactly three irregular verbs in the entire language (ser, ir and ver), plus their derivatives. Every other verb, however badly it behaves elsewhere, is perfectly regular here.
ser: era, eras, éramos…
ir: iba, ibas, íbamos…
ver: veía, veías, veíamos…
Even tener, irregular in the present, the preterite and the future, is a plain tenía here. Compare tener across its tenses, or ser for one of the three that do change.
A phrase you will use constantly
Había, the imperfect of haber, means “there was” or “there were”, and it is how Spanish describes what a scene contained: había mucha gente (“there were a lot of people”). One form covers singular and plural, and it is one of the most frequent words in any story told in the past.