Are the following sentences correct, gramatically? If yes, is there any difference in meaning between them?

1. Teacher spoke to the concerned parents

2. Teacher spoke to the parents concerned

Gramatically they are correct, although adding the at the beginning would make them sound better.

In the first sentence, the teacher spoke to the parents; in the second one the concerns are addressed.

Where you place the adjective "concerned" makes a difference. In sentence #1 it is clear the parents were concerned. In #2 it could be the teacher was concerned. Go with Anonymous' suggestion of beginning #1 with "The" but I would not use sentence #2.

Sra

Yes, both sentences are grammatically correct. However, there is a slight difference in meaning between them.

1. "Teacher spoke to the concerned parents."
In this sentence, the word "concerned" is an adjective that describes the parents. It implies that the parents are worried, anxious, or troubled about something specific. The teacher spoke to the parents who are directly involved or affected by the situation being discussed.

2. "Teacher spoke to the parents concerned."
In this sentence, the word "concerned" functions as a participle that modifies the noun "parents." It implies that the parents are the ones who are concerned or interested in a particular matter. The teacher spoke to the parents who have a specific interest or involvement in the topic being discussed.

In summary, the first sentence emphasizes that the parents are worried, while the second sentence emphasizes that the parents have a particular interest or involvement.