Acronym

====Vietnamese====
In [[Vietnamese language|Vietnamese]], which has an abundance of compound words, initialisms are very commonly used for both proper and common nouns. Examples include ''TP.HCM'' ({{lang|vi|Thành phố Hồ Chí Minh}}, '[[Ho Chi Minh City]]'), ''THPT'' ({{lang|vi|trung học phổ thông}}, 'high school'), ''CLB'' ({{lang|vi|câu lạc bộ}}, 'club'), ''CSDL'' ({{lang|vi|cơ sở dữ liệu}}, 'database'), ''NXB'' ({{lang|vi|nhà xuất bản}}, 'publisher'), {{lang|vi|ÔBACE}} ({{lang|vi|ông bà anh chị em}}, a general form of address), and {{lang|vi|CTTĐVN}} ({{lang|vi|các Thánh tử đạo Việt Nam}}, '[[Vietnamese Martyrs]]'). Longer examples include ''CHXHCNVN'' ({{lang|vi|Cộng hòa Xã hội chủ nghĩa Việt Nam}}, 'Socialist Republic of Vietnam') and ''MTDTGPMNVN'' ({{lang|vi|Mặt trận Dân tộc Giải phóng miền Nam Việt Nam}}, '[[Viet Cong|Liberation Army of South Vietnam or the National Liberation Front of South Vietnam]]'). Long initialisms have become widespread in legal contexts in [[Vietnam]], for example ''TTLT-VKSNDTC-TANDTC''.<ref>{{cite web |title=Từ viết tắt |trans-title=Abbreviations |publisher=[[BBC Academy]] |access-date=September 4, 2017 |url= https://www.bbc.co.uk/academy/vietnamese/article/art20131007102738486 |language=vi |quote=Chưa kể cách viết này còn dễ bị cho là lười biếng hoặc tỏ ra quan trọng, vì đây là cách chép nguyên xi, máy móc các cụm từ viết tắt từ văn bản pháp quy của chính quyền, như TTLT-VKSNDTC-TANDTC, khá phổ biến ở Việt Nam hiện nay. |archive-url= https://web.archive.org/web/20171120141047/http://www.bbc.co.uk/academy/vietnamese/article/art20131007102738486 |archive-date=November 20, 2017 |url-status=live}}</ref> It is also common for a writer to coin an ad hoc initialism for repeated use in an article.

Each letter in an initialism corresponds to one [[morpheme]], that is, one syllable. When the first letter of a syllable has a tone mark or other diacritic, the diacritic may be omitted from the initialism, for example {{lang|vi|ĐNA}} or {{lang|vi|ĐNÁ}} for {{lang|vi|Đông Nam Á}} ('[[Southeast Asia]]') and ''LMCA'' or {{lang|vi|LMCÂ}} for {{lang|vi|Liên minh châu Âu}} ('[[European Union]]'). The letter {{lang|vi|[[Ư]]}} is often replaced by ''W'' in initialisms to avoid confusion with ''U'', for example ''UBTWMTTQVN'' or {{lang|vi|UBTƯMTTQVN}} for {{lang|vi|Ủy ban Trung ương Mặt trận Tổ quốc Việt Nam}} ('Central Committee of the [[Vietnamese Fatherland Front]]').

Initialisms are purely a written convenience, being pronounced the same way as their expansions. As the [[Vietnamese alphabet#Letter names and pronunciation|names of many Vietnamese letters]] are disyllabic, it would be less convenient to pronounce an initialism by its individual letters. Acronyms pronounced as words are rare in Vietnamese, occurring when an acronym itself is borrowed from another language. Examples include {{lang|vi|SIĐA}} ({{IPA-vi|s̪i˧ ˀɗaː˧|pron}}), a respelling of the French acronym ''SIDA'' ('[[AIDS]]'); ''VOA'' ({{IPA-vi|vwaː˧|pron}}), a literal reading of the English initialism for '[[Voice of America]]'; and ''[[NASA]]'' ({{IPA-vi|naː˧ zaː˧|pron}}), borrowed directly from the English acronym.

As in [[#Chinese|Chinese]], many compound words can be shortened to the first syllable when forming a longer word. For example, the term {{lang|vi|[[Viet Cong|Việt Cộng]]}} is derived from the first syllables of {{lang|vi|Việt Nam}} ('Vietnam') and {{lang|vi|Cộng sản}} ('communist'). This mechanism is limited to [[Sino-Vietnamese vocabulary]]. Unlike with Chinese, such [[clipped compound]]s are considered to be [[portmanteau]] words or [[blend word]]s rather than acronyms or initialisms, because the [[Vietnamese alphabet]] still requires each component word to be written as more than one character.