[eng] Although lenition processes have been traditionally analysed from a segmental perspective, they can also affect whole lexical and functional units. This is the case of the Spanish preposition 'de', which can be deleted in casual speech and in certain syntactic constructions (e.g. noun complements) (see Rigau 1999, Suñer 1999, Estrada 2016). Some authors have shown that de deletion is a very common phenomenon, especially in certain geographical areas (see Arjona 1978, 1979, Sosa Alonso 2003, Gómez 2014 as a few examples). Our aim in this paper is to analyse the production of 'de' in spontaneous speech in order to check whether lenition is really affecting the preposition. We will approach the topic from a phonetic and experimental standpoint. The results demonstrate that the production of 'de' renders a lot of phonetic variation, which can be organized in a hyper to hypoarticulation continuum. Speakers seem to choose from the pool of variants according to (i) the preceding phonetic context and (ii) the distance from the last lexical stress: they prefer hypoarticulated realizations (including deletion) after a vowel and at least two syllables away from stress, whereas they tend to select hyperarticulated realizations after a pause or a consonant and in a posttonic syllable. The syntactic value of the prepositional phrase does not seem to condition the reduction of 'de'.