The distinction between syntagmatic compounds of the type N Prep N, such as Fr. jouet d?enfant, and nominal syntagms of the type N Prep N, such as the partially equivalent Fr. jouet pour enfants, remains unclear and vague. This is mainly because the lexical and syntactic status of syntagmatic compounds still is controversial. In some cases, as in jouet d?enfant and jouet pour enfants, partial equivalent syntagmatic compounds and nominal syntagms may coexist and underlie a specific variation and alternation. In other cases, such as Pt. bracelete de aço and bracelete em aço, two variants of a syntagmatic compound may alternate and coexist. The first part of this paper provides an overview of the current discussion on these two types of constructions. The second part addresses the alternation and variation of syntagmatic compounds and nominal syntagms by means of analysis of large-scale corpus data, the French, Spanish and Portuguese corpus of the TenTen family. Here, the focus lies on the variation of the prepositional internal element of these constructions as well as on a comparison of different word formation patterns.