The neural correlates of language processing have been mostly studied from a perceptive point of view (i.e. while listening or reading). Studies with speaking are instead rarer, because fMRI is very sensitive to movement in the scanner, such as the movement of the jaw elicited by speaking. In addition, it is harder to run experiments where participants speak, because it is almost impossible to have experimental control over what participants will say, without telling them exactly what to say (for example by reading). Therefore, the aim of this thesis was to focus on brain activity during the productive side of language, and to understand to what extent what we learnt about language comprehension can be extended to language production. This thesis presents four studies that focus on different aspects of sentence production and comprehension with different tasks. Three chapters focus on brain activity and the connectivity between brain regions during syntactic processing, using both a task design and a naturalistic paradigm. One chapter focuses on the neural responses to compositional processing during sentence production. The results suggest that there are some differences in the brain responses to production and comprehension, both spatially and in the timing of responses, but overall it appears that the same brain regions are used for linguistic processing during speaking and listening.