If a portal leads to 1888 and the time travelers are talking about an event in 1889, they use the future tense.
Superman: My father is observing Jonathan and Martha who will become my foster parents when I.
To which beach did you travel? Did you see this note a link to a different post, which was written after this but posted yesterday? Svetz's solution to a time paradox involving the destruction of Ford's Model-T demonstrates very well how bad English is with time travel: Svetz: Maybe we can go around you.