In the Valencian Community in Spain, the coexistence of Spanish and Catalan as co-official languages and English as a foreign language, which is learned as a third language (L3), shapes a unique multilingual setting. This study examined the extent to which multilingual learners’ use of two interpersonal pragmatic markers (PMs), i.e., hedges (e.g., I believe) and attitude markers (e.g., fortunately), is related across languages and whether the relationship changes over time. Participants were 313 Spanish-Catalan bilingual high school learners of L3 English. They wrote three opinion essays over one academic year in the three languages of instruction: Spanish, Catalan, and English. Quantitative results revealed a trend towards stronger correlations over time in both PMs. At Time 3, correlations were statistically significant for all language pairs in hedges and for two language pairs in attitude markers (Spanish and Catalan, Spanish and English). Qualitative analyses of the learners’ essays lend support to these results and show transfer at the phrase and discourse-level.