This thesis aims to study the phenomenon of linguistic interference in the use of the verb ser in different marital status (single, married and divorced) in spanish spoken by catalans living in different territorial areas of Catalonia. Our theory is that individuals who reside in territorial areas where catalan is the most spoken language tend to use the verb ser + marital status rather than the verb estar + marital status due to the influence of catalan. We have used a quantitative methodology, i.e. we have collected data through a survey. The results of our study confirm our theory that individuals who reside in territorial areas where catalan is the most spoken language tend to use the verb ser + marital status rather than the verb estar + marital status due to the influence of catalan.