vocative:mention: Twitter mentions
The specialization of vocative, vocative:mention is used in PoSTWITA for Twitter @-mentions and it links the addressee (i.e. the used called out by means of the @-mention) to its host sentence;
@user mi sono davvero divertito
vocative:mention(divertito, @user)
However, just like hashtags, whenever they are syntactically integrated into the sentence, they are annotated according to their actual syntactic role.
arriva @user
nsubj(arriva, @user)
vocative:mention in other languages: [ga] [it] [ro]