10 Common Beginner Mistakes In Chinese Part 1

1. 学 vs 学习 (xué / xuéxí)
Both words mean ‘to study’ or ‘to learn’, whereas 学习 can be used both transitively and intransitively, 学 in normally reserved for transitive use.
e.g.
我学（习）汉语，她学（习）法语。Wǒ xué(xí) hànyǔ, tā xué(xí)fǎyǔ.
I study Chinese, she studies French.
我学习，他不学习。Wǒ xuéxí, tā bù xuéxí.
I learn, he doesn’t learn.
In the second sentence, the word 习 cannot be omitted.

2. 认识 vs 知道 (rènshi / zhīdào)
认识(rènshi): to know (be familiar with)
知道(zhīdào): to know (facts)

Compare:
你知道乔治 克鲁尼（George Clooney）吗？Nǐ zhīdào George Clooney ma?
Do you know George Clooney?
是的，我知道他。Shìde, wǒ zhīdào tā.
Yes, I know him.
▲Ling: you know him because of his films, ads, or other media.
你认识乔治 克鲁尼（George Clooney）吗？Nǐ rènshi George Clooney ma?
Do you know George Clooney?
▲Ling: although the English translation is the same as the ‘知道’ sentence, this sentence comprises another meaning: are you familiar with him? In other words, are you a friend of him? Do you know well his personalities? etc.
我知道George Clooney，但是我不认识他。Wǒ zhīdào George Clooney, dànshì wǒ bú rènshi tā.
I know George Clooney, but I am not familiar with him.

Therefore, 认识(rènshi) can be understood as a deeper or better knowing than 知道(zhīdào).

Let’s see another example:
你认识她吗？Nǐ rènshi tā ma? 
Do you know her?
不认识，但我听说过她。Bú rènshi, dàn wǒ tīngshuō guò tā.
No, but I’ve heard about her.
Set phrases:
很高兴认识你！Hěn gāoxìng rènshi nǐ!
Nice to meet you!
你是在哪里认识她的？Nǐ shì zài nǎlǐ rènshi tā de?
Where did you get to know her?

3. 姓 vs 贵姓 (xìng / guìxìng)
‘姓’(xìng) and ‘贵姓‘(guìxìng) both mean ‘Surname’, the difference is: ‘贵姓'(guìxìng) is formal, ‘姓'(xìng) is less formal. ‘贵'(guì) is a courteous word used here to show the respect. ‘贵姓’(guìxìng) can only be used in the ‘您贵姓?’ (guìxìng) sentence. However, ‘姓'(xìng) has other usages. When you reply the question ‘您贵姓?’(nín guìxìng)，remember to drop the honorific ‘贵’(guì).
The most common mistake:
Wrong: 你贵姓什么? Nǐ guìxìng shénme?
Correct: 你姓什么？Nǐ xìng shénme?
Other proper ways of asking someone’s surname politely in Chinese is ‘您姓什么？’(nín xìng shénme?). In spoken language, you may also hear people sometimes saying ‘怎么称呼您？’(zěnme chēnhu nín?)or ‘您怎么称呼？’(nín zěnme chēnhu?), which literally means ‘How (do I) address you?’. Either of them is correct.

4. 学院 vs 学校 vs 大学 vs 系 (xuéyuàn / xuéxiào / dàxué / xì)
学院(xuéyuàn)： institute, college
学校(xuéxiào)：school
大学(dàxué)：university 
系(xì): department, faculty 
Normally, in China, a ‘大学'(dàxué) has many ‘学院’(xuéyuàn), a ‘学院'(xuéyuàn) includes different ‘系'(xì),  ‘系'(xì) is also major. Sometimes, ‘学院'(xuéyuàn) can also be a university by itself, for example, Business College (商学院shāng xuéyuàn).

5. 几 vs 多少 (jǐ / duōshǎo)
Both of these can be used to mean “how many” or “how much”. Whereas ‘几'(jǐ) should be used with a measure word, ‘多少'(duōshǎo) can be used either with or without a measure word for the noun it modifies.
你有几本词典? Nǐ yǒu jǐ běn cídiǎn?
How many dictionaries do you have? 
你有多少 (本 )词典?  Nǐ yǒu duōshǎo (běn)cídiǎn?
How many dictionaries do you have?
The measure word ‘本'(běn) is a must for the first sentence, but only optional in the second.
Also, when ‘几'(jǐ) is used, the expected answer is usually under 10, whereas ‘多少'(duōshǎo) can be used whether one expects a large or small answer.
你们大学有多少学生？Nǐmen dàxué yǒu duōshǎo xuésheng?
How many students are there at your university?
你家有几个人？Nǐ jiaā yǒu jǐ gè rén?
How many people are there in your family?