# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\s+\((?:[^)(]+|\((?:[^)(]+|\([^)(]*\))*\))*\)//gm;t' <<< "Rwanda (/ruˈɑːndə, -ˈæn-/ (About this soundlisten); Kinyarwanda: U Rwanda [u.ɾɡwaː.nda] (About this soundlisten)), officially the Republic of Rwanda (Kinyarwanda: Repubulika y'u Rwanda; Swahili: Jamhuri ya Rwanda; French: République du Rwanda)..."
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html