lo que decía

what was being said

→ lo
phrase Uncommon #21,868
what was being said Refers to the content of what someone said; the person speaking is usually understood from context.
SP: No entendí lo que decía el profesor.
EN: I didn't understand what the teacher was saying.

Al no entender lo que decía, no escuché más.

Since I didn't understand what he was saying, I didn't listen anymore.

Debería haber escuchado lo que decía mi madre.

I should have listened to what my mother was saying.

Creí que no estaba segura de lo que decía.

I thought she wasn't sure what she was saying.

Leí un artículo en japonés, y luego expliqué lo que decía en español.

I read an article in Japanese, and then explained what it said in Spanish.

Tom no se podía creer lo que decía Mary.

Tom couldn't believe what Mary was saying.

Un hombre nunca debe correr, es lo que decía mi padre.

A man should never run, that's what my father used to say.

— Tampopo (1985)

Tom no parecía interesado en lo que decía Mary.

Tom didn't seem interested in what Mary was saying.

Kikuchiyo tenía razón en lo que decía.

Kikuchiyo was right in what he said.

— Los siete samuráis (1954)

Entendí lo que decía.

I understood what he was saying.

Tom apenas podía entender lo que decía Mary.

Tom could barely understand what Mary was saying.

Tom admitió que lo que decía estaba mal.

Tom admitted that what he said was wrong.

Seguro que no sabía lo que decía.

He surely didn't know what he was saying.

— Locuras de verano (1955)

Pero nadie sabe lo que decía la nota.

But nobody knows what the note said.

Porque hago siempre lo que decía mi abuelo.

Because I always do what my grandfather said.

— El espíritu de la colmena (1973)

Ya que Tom hablaba en francés, yo no podía entender lo que decía.

Since Tom was speaking French, I couldn't understand what he was saying.