Common Points
Both “学” (xué) and “学习” (xuéxí) can be used as verbs, meaning “to study” or “to learn.”
e.g.
我们学/学习汉语四年了。(Wǒmen xué/xuéxí hànyǔ sì nián le.)
We have been studying Chinese for four years.
他才5岁就开始学/学习电脑了。(Tā cái 5 suì jiù kāishǐ xué/xuéxí diànnǎo le.)
He started learning about computers at the age of 5.
大家学/学习得很努力。(Dàjiā xué/xuéxí de hěn nǔlì.)
Everyone is studying very diligently.
Differences
As a verb
1. “学” (xué) can also mean “to imitate” or “to mimic.”
e.g.
别学我说话！(Bié xué wǒ shuōhuà!) Don’t imitate the way I speak!
✘ 别学习我说话！
这种坐姿一般人学不了。(Zhè zhǒng zuòzī yībān rén xué bù liǎo.) Most people can’t learn this kind of sitting posture.
✘ 这种坐姿一般人学习不了。
2. “学习” (xuéxí) can mean “to emulate” and can be used in phrases like “向/跟……学习” (xiàng/gēn… xuéxí), meaning “to learn from” or “to emulate.”
The object of “学习” (xuéxí) is generally knowledge or skills and cannot refer to a person. The structure “向/跟……学习……” (xiàng/gēn… xuéxí) is a commonly used construction.
e.g.
请大家向班长学习，多么负责啊！(Qǐng dàjiā xiàng bānzhǎng xuéxí, duōme fùzé a!)
Please learn from the class monitor; how responsible they are!
我们要向有经验的人学习技术。(Wǒmen yào xiàng yǒu jīngyàn de rén xuéxí jìshù.)
We should learn technical skills from experienced individuals.
你要向这位英雄学习不怕死的精神。(Nǐ yào xiàng zhè wèi yīngxióng xuéxí bùpàsǐ de jīngshén.)
You should learn the fearless spirit from this hero.
As a noun
“学” (xué) can function as a noun with meanings like “learning,” “knowledge,” “subject of study,” “branch of learning,” or “school/college.” “学习” (xuéxí) does not have these meanings.
e.g.
张老师是一位著名的学者。(Zhāng lǎoshī shì yī wèi zhùmíng de xuézhě. )
Teacher Zhang is a renowned scholar.
我们要有一些语言学的知识。（Wǒmen yào yǒu yīxiē yǔyán xué de zhīshi.）
We should have some knowledge of linguistics.
她还在那个中学上学。（Tā hái zài nàge zhōngxué shàng xué.）
She is still attending that middle school.
Summary
“学” (xué) and “学习” (xuéxí) both function as verbs with the primary meaning of “to study” or “to learn.” However, “学” (xué) has the additional meaning of “to imitate” or “to mimic” and is more versatile in its usage. On the other hand, “学习” (xuéxí) can mean “to emulate” and is often used in phrases like “向/跟……学习” (xiàng/gēn… xuéxí) to convey “learning from” or “emulating” someone or something. Importantly, “学习” (xuéxí) is used specifically when referring to acquiring knowledge or skills and cannot be applied to individuals. Furthermore, “学” (xué) can serve as a noun with various meanings like “learning,” “knowledge,” “subject of study,” “branch of learning,” or “school/college,” while “学习” (xuéxí) does not have these noun-related meanings.
Exercise
