It is a curiosity of present-day media discourse that the Pashto phrase loya jirga ‘grand council’ is constantly being cited (generally, without translation) in its autochthonous form instead of being translated into English, as would a comparable phrase in any other foreign language.
Here is (an admittedly speculative) explanation. The two words in Pashto (the national language of Afghanistan) fit nicely into what is the standard––and likely most frequent––phrase pattern of English, viz. two dissyllabic words with stress on the initial syllable in both; cf. fatty acid, funny money, loyal member, etc., etc. In addition, use of the Pashto phrase obviates the need for a slightly more cumbersome English equivalent like grand assembly or grand council, where one might be unsure as to which noun would fit better, assembly or council.
Finally, to clinch the case, for a media outlet the use of an easily pronounceable foreign phrase is advantageous because it is (1) unambiguous; and (2) connotes a possible (though almost certainly spurious) purport, namely, knowledge of an exotic foreign language. The latter is important because it imparts a kind of subcutaneous authenticity to the media report and its source that cannot be signified in any other way.