The aim of this work is to describe and analyse the linguistic attitudes of the inhabitants of the trilateral Brasil-Colombia-Peru border towards Portuguese and Spanish residents in the area, as well as the phenomenon of alternations and linguistic interference arising from contact. Through the technique of interview and direct observation, attitudes are described in terms of cognitive, emotional and behavioural dimensions, and discover high percentages of negative assessments and self-assessments against the forms of speech studied, suggesting a situation of linguistic discrimination in addition to the existing social discrimination. The aim of the present work is to describe and analyse the linguistic attitudinal of people at the tri-border among Brazil, Colombia, and Peru towards the Spanish and Portuguese varieties spoken in the area, and towards the promotion of linguistic diversity and interference resulting from linguistic contact. By means of means of exchanges and direct observation, the article attempts to describe the linguistic attitude from three dimensions: Cognitive, Affective and Behavioral. Data analysis shows that is a high level of negative attitude and negative self-attitude towards these speech varieties. Results indicate a situation of linguistic stigmatisation that is added to the ongoing social discrimination. Thus, the study proposals the implementation of linguistic policies that promote the local speech forms through mass media and education in order to guarantee a process of consolidation of linguistic democracy, which in turn will lead to equity and social justice.