I was wondering if there are some words that describe the characteristic of some person that does not keep up with some supposed pace.
For example, in orchestra performance by a team, one performer playing his instrument always lags behind by a certain amount of time.
Another example, unlike other students, a student seldom ask questions in classes. But he asks a lot of questions after classes. The reason is that he needs more time to think in classes than other students, so not able to keep up with the paces of the classes and not to say to ask questions (although I don't think it is a bad thing).
Best Answer
You could call the person a laggard, or say that they are always playing catch-up, always bringing up the rear, running behind, falling behind, not keeping up, or that they are consistently delayed. These all have negative connotations.
You could also say that they 'march to a different tune' or 'march to the beat of a different drum', or 'do things in their own time', which can be positive or negative depending on how they're used.