We investigated the processes of lexical retrieval during the production of adjectival noun phrases (NPs) such as "the blue kite". We used various current assumptions about the scope of grammatical and phonological encoding and about the locus of the classic frequency effect to derive predictions about possible frequency effects in the NP naming task. The predictions were tested in two picturenaming experiments where we manipulated orthogonally the frequencies of the adjective and of the noun that composed the NPs. We consistently found frequency effects for both adjectives and nouns. Moreover the effects were additive. We argue that the existence of a frequency effect for the noun during noun phrase production restricts the various combinations of assumptions that speech production models can hold simultaneously. Possible implications of the additivity of the effects for the time course of lexical access are also discussed. 3 The study of the mechanisms and representations involved in speech production has mainly focused on single word retrieval. Much less is known about the production of multi-word utterances. In order to produce this type of utterance the speech production system needs to retrieve several lexical units and to organize them into a well-formed utterance. According to current models of speech production (e.g., Levelt, Roelofs, & Meyer, 1999), the linguistic mechanisms involved in this process can be divided in three main components: grammatical, phonological, and phonetic encoding. In this article we address some issues about the organization of these components. We report two picture naming experiments where participants had to name pictures by using adjectival noun phrases (NPs) of the form determiner + adjective + noun (e.g., "the blue kite"). Spec...