Did the Portuguese influence how days of the week are named in Vietnamese and Chinese?

Question

The Portuguese were some of the first colonizers / missionaries in the Far East. In the case of Vietnam, they created the first phonetic transcription of the language. Interestingly, nowadays the Vietnamese use numbers for days of the week in almost exactly the same way as the Portuguese. Both languages have an exception for Sunday (domingo and chủ nhật in Portuguese and Vietnamese, respectively). They also regard Monday as the second day of the week.

1. So, did Portuguese indeed influence Vietnamese in that matter?

2. Did Portuguese influence Chinese too? I am aware of this question, as the Chinese also use numbers for the days of the week (even though Monday is marked with number 1).

Answer 1

This is a summary of the information on CJV Lang, which has a much more detailed view on the naming of the 7-day week across many languages.

But in essence:

• Neither dynastic China nor Vietnam had a real concept of a 7-day civilian week. The 10-day cycle 旬 xún was more common.
• Contact with Buddhism, especially in the 8th century, brought the 7-day cycle to astrological use, but this was a rather niche use in China and Vietnam, although the Japanese had the 具注暦 guchūreki from at latest 1000.
• Contact with Christianity (starting with Jesuit missions) and Western trade from the 15th - 19th centuries introduced the concept of the 7-day week to daily life in certain parts of East Asia.
• Vietnam was strongly influenced by Portuguese missionaries, with their Roman Catholic background and linguistic preference for the numbering of the feria. It started the week on Sunday as "the Lord's day". The influence of general literacy in quốc ngữ was a profound factor in the spread of the 7-day week in this territory.
• China adopted the 7-day week more through Western trade, with the term 禮拜 lǐbài "worship" being semantically extended to "day of worship" and then "7-day week" in the southern topolects (like Cantonese and Hokkien), attested in this extended meaning in 1828.
• The specific mechanism by which the numbers were added in China is not clear, and is assumed to be a local innovation. But it becomes common in colloquial speech in late 19th-century China, even if the term 禮拜 lǐbài in this way is repudiated by the literati.
• The term 星期 xīngqī appears in print in 1889 in Chinese, and repurposes an older term referring to Qixi Festival (七夕) / Star Festival. It becomes official after the establishment of the Republic of China in 1912.
• A later re-importation of 週 zhōu into China occurred around the turn of the 20th century, probably from Japanese sources, and is quickly accepted.
• Certain Chinese Catholics at some point apparently used 瞻禮 zhānlǐ in a similar way to Portuguese and Vietnamese (with Monday as 2nd), in liturgical contexts. This has now died out.