Break indices of level 0 (BI 0) are used to mark cohesion between orthographic words. Orthographic words separated by BI 0 constitute a prosodic word (PrWord) that may bear only one pitch accent.
Example
¿La has visto, a María?
[Have you seen Mary?]
In this example, there are five orthographic words, but only three PrWords.
The first PrWord is La has, constituted of two orthographic words, the clitic pronoun La and the auxiliary verb has. The second PrWord is visto, constituted of a unique orthographic word, which is the past participle of the verb ver [to see]. The right-dislocated element a María, is the last PrWord, constituted of the preposition a and the proper name María.
When a PrWord is constituted by more than one orthographic word, these orthographic words are separated by break indices of level 0, since they don't constitute a PrWord on their own and, at most, one of them can bear a pitch accent. For example, in the first PrWord, the clitic pronoun La cannot bear any pitch accent and has to be combined with the auxiliary verb has to constitute a PrWord, so La and has are separated by a BI 0. In the same way, in the third PrWord, the preposition a and María are separated by a BI 0, since only María can bear a pitch accent, whereas a on its own could not.
