Based on your shown samples, could you please try following. Please make sure you clear your cache before testing your URLs.
RewriteEngine ON
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]*)/([^/]*)/?$ index.php?lang=$1&path=$2 [L]
OR as per OP's comment use QSA flag along with L
flag to append previously passed query string to newly build one in above rules.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…