又……又…… ‘both… and…’ indicates that the subject performs two concurrent actions that coexist within the same general time frame, or can express the coexistence of two qualities or attributes of the same subject. The pattern yìbiān… yìbiān… 一边/一邊……一边/一邊…… ‘… while … at the same time’ expresses two simultaneous actions performed by the subject. The pattern …, yě… ……,也……‘…, and (also)…’ is often used to express sameness or similarity between two or more things related to the same subject or to different subjects. With one subject, it links parallel actions or states for emphasis. Across subjects, it highlights shared traits or actions.
For explanation of the structure, check Coordinative structure with yòu… yòu… 又……又…… ‘both… and…’ ,Structure with yìbiān… yìbiān… 一边/一邊……一边/一邊…… “… while … at the same time” and Coordinative structure with …, yě… ……,也…… ‘…, and (also)…’
Differences
1. Expressing two actions performed by the subject
All three patterns can describe two or more actions carried out by the subject. However, yòu… yòu… 又……又…… ‘both… and…’ indicates that two concurrent actions occur within the same general time frame, indicating that they having been done altogether, but not necessarily on strict simultaneity.
Yìbiān… yìbiān… 一边/一邊……一边/一邊…… ‘… while … at the same time’ emphasizes that the subject carries out two actions at once, indicating that they have been done at the same time, highlighting simultaneity.
Sometimes, the simultaneity expressed by yìbiān… yìbiān… 一边/一邊……一边/一邊…… may extend over a relatively long period of time, during which the subject performs two ongoing activities at the same time.
Yòu… yòu…又…又… can mention the same two activities and simply states that both were happening during that period, without highlighting simultaneity.
Note that, the pattern yìbiān… yìbiān… 一边/一邊……一边/一邊…… focuses on simultaneity and cannot be followed by verbs expressing willness or intention (e.g., xiǎng 想 ‘to wish’,yào 要 ‘to want’), psychological activities (e.g., xǐhuān 喜欢 ‘to like’,juéde 觉得 ‘to feel’) or modal verbs (e.g., huì 会 ‘to be able’,néng 能 ‘to can’). In these cases, the patterns yòu… yòu… 又……又…… or … yě… ……也…… can be used.
The pattern …, yě… ……,也…… ‘…, and (also)…’ cannot be used to express two concurrent actions on strict simultaneity. The reason is that …, yě… ……,也…… ‘…, and (also)…’ focuses on the similarity instead of ongoing events. That is, the two events should have something in common, no matter they occur at the same time or not.
To learn more about the pattern yìbiān… yìbiān… 一边/一邊……一边/一邊…… with two different subjects, check Structure with yìbiān… yìbiān… 一边/一邊……一边/一邊…… “… while … at the same time”
2. Expressing two qualities or states of the subject
The pattern yòu… yòu… 又……又…… ‘both… and…’ can emphasize the coexistence of two qualities or states of the same subject. In this use, each yòu 又 is usually followed by an adjective functioning as a predicate, and it cannot be preceded by adverbs of degree, such as hěn 很 ‘very’. The pattern …, yě… ……,也…… ‘…, and (also)…’ can also be used in this way, but its tone is more neutral, as it simply adds another characteristic of the subject which is in some way similar to the previous one. In this structure, adverbs of degree can be used with this pattern. By contrast, yìbiān… yìbiān… 一边/一邊……一边/一邊…… focuses on two simultaneous actions and is not used to describe two qualities of a subject.
Note that, verb phrases describing the subject’s identity or state, such as shì 是 ‘to be’, yǒu 有 ‘to have’ or dāng 当/當 ‘to serve as’, can also appear with the pattern yòu… yòu… 又……又…… or … yě… ……也……, but never with yìbiān… yìbiān… 一边/一邊……一边/一邊…….