Learn Hardcore Spanish (Latin America): Recibí una llamada en mi celular mientras esperaba en el embotellamiento. - I received a call on my cell phone while I was waiting in the traffic jam.

Spanish speakers use the preterite to narrate a single, completed action in the past. He recibido (present perfect) is reserved for events that still have a link to the present or in some regions (mainly Spain) to talk about very recent events. In Latin American Spanish, you say recibí to simply state “I received” without implying any ongoing relevance.

Why is esperaba in the imperfect rather than a preterite form like esperé?

The imperfect tense describes an ongoing, background action—in this case, the act of waiting in traffic. It sets the scene for another event (receiving the call). If you said esperé, you’d be treating the waiting itself as a completed, punctual action, which doesn’t convey “I was stuck in traffic” at the moment the call arrived.

What’s the difference between mientras and cuando here? Could I say cuando esperaba en el embotellamiento?

Mientras emphasizes two actions happening simultaneously over a period of time (“while I was waiting”). You could use cuando with the imperfect (cuando esperaba) to mean “when I was waiting,” but mientras more clearly highlights the parallel nature of waiting and receiving the call.

Why does the sentence use celular instead of móvil or teléfono móvil?

In Latin America, celular is the everyday word for a mobile phone. In Spain, people more often say móvil. You could also say teléfono celular or just teléfono, but celular is by far the most common term in Latin American countries.

What does embotellamiento mean? Is it just “traffic”?

Embollamiento literally refers to cars being “bottled up,” so it means traffic jam—a standstill or very slow traffic. The word tráfico means “traffic” in general (flow of vehicles). For the jam itself, Latin American speakers say embotellamiento; in Spain they use atasco.

Why is there an article in en el embotellamiento? In English we often say “in traffic” without the.

Spanish normally requires a definite article before nouns like this when talking about a specific situation. You’re referring to the particular traffic jam you were stuck in, so you say en el embotellamiento. Saying en embotellamiento would sound odd to a native speaker.

Could I replace recibí una llamada with me llegó una llamada or mi celular sonó?

Yes.

Me llegó una llamada (“a call came to me”) is perfectly natural and emphasizes the incoming call.
Mi celular sonó (“my phone rang”) focuses on the ring rather than the act of receiving.
All are correct; you choose based on whether you want to stress receiving, the phone ringing, or the call arriving.