A couple of lovers is/are taking a walk ...

Are.

You could say "the couple is taking a walk," but "a couple of..." clearly indicates "are."

Very interesting. Clearly native speakers are influenced by notional plurality.

Thanks, Sozobe and JTT.

Something whis has not yet been mentioned is that although the word "couple" means, informally, "two" or "a small number greater than one" (approximately or exactly depending on context), it means something different when applied to a relationship between two people. It is a noun, not a quantity, and does not have "of" after it. It is usually implies that the relationship is established.

A couple of minutes (a short time)
A couple of dollars (a small amount of money greater than one dollar)
A couple of years (perhaps 18 to 30 months)

but...

A married couple.
A gay couple.
A long-established couple.
An elderly couple.
We met a very nice couple from Yorkshire.
In our hotel, a honeymoon couple is in room 27.

For this reason, a native speaker would probably not talk about a "couple" of lovers. (Lovers haven't been together very long, their relationship is not formally defined in the same way as that of a "couple".

One might talk of a pair of lovers. The noun "pair" can be followed by a singular or plural verb. The singular is always used when pair or couple refers to a set considered as a single entity: this pair of shoes is on sale. The married couple for room 27 has arrived.

For both couples and pairs. a plural verb is used when the members are considered as individuals. The pair are working more harmoniously now. The pair of lovers are walking hand-in-hand. The couple in room 27 are both redheads.

Thanks, Contrex.

Points noted.

Oh dear! I made a couple of errors.





Of course I meant "something which" and "it usually implies".