Speaking during Tavaf is permissible and does not invalidate it. Hz. Peygamber (sallallahu aleyhi ve sellem) said: 'Tavaf around the House is like namaz, except that Allah has permitted speaking in it. So whoever speaks in it, let him speak only good.' This hadith establishes that while talking is allowed, it should be purposeful and good speech rather than idle chatter.
The sunnet practice during Tavaf is to engage in dhikr (remembrance of Allah), dua (dua), istighfar (seeking forgiveness), and Kur'an recitation. You may supplicate in any language — Arabic is not required for personal duas. There are no specific mandatory duas assigned to each circuit, despite what some printed Tavaf dua booklets may suggest. Those circuit-specific duas are later compilations, not from Hz. Peygamber's practice. The only Sunnah-specific dua is between the Yamani corner and the Hacer-ul Esved: 'Rabbana atina fi'd-dunya hasanah wa fi'l-akhirati hasanah wa qina adhab an-nar.'
Brief necessary conversation with companions — such as coordinating meeting points, checking on someone's well-being, or answering important questions — is fine. However, extended worldly discussions, arguments, gossiping, phone calls about business, and loud talking that disturbs others should be avoided. Use the precious time of Tavaf to connect with Allah through heartfelt dua.