<p>Datshiane Navanayagam speaks to two women who research what happens to our thoughts, feelings and behaviours when we speak many languages. To what extent do we have a “mother tongue” – and what happens if we stop using it?</p><p>Dr Aneta Pavlenko is a Ukrainian-American linguist who looks at the emotional impact of moving between languages. </p><p>Professor Núria Sebastián Gallés is a Spanish cognitive psychologist who studies bilingual toddlers and young babies. </p><p>Produced by Rebecca Moore and Hannah Sander</p><p>(Image: (L) Aneta Pavlenko, courtesy Aneta Pavlenko. (R) Núria Sebastián Gallés, courtesy Núria Sebastián Gallés.)</p>