〜ように言う|〜ようにゆう

1. 1Tell someone to do something, reporting an instruction or request indirectly.Ex. 1
2. 2With the negative form, tell someone not to do something.Ex. 2

It is neutral in register and is typical when relating what a parent, teacher, boss, or doctor told someone to do. It turns a direct command like 寝なさい or 忘れないでください into reported speech. Similar verbs such as 頼む or 伝える can replace 言う in the same frame.

• ようにするN4「ようにする」 means taking care or making an effort to do (or avoid doing) something yourself, or working to bring about a certain state, and does not itself report an instruction; 「ように言う」 reports an instruction telling someone else to do (or not do) something. The two attach in similar ways but are not interchangeable.
• ようになるN4「ようになる」 reports no instruction; it expresses a change in ability or habit over time, either going from unable to able or starting to do something regularly, and for ability it often follows the potential form, typically as 「ようになった」. The two simply share 「ように」 and are not interchangeable.
• てくださいN5「てください」 makes a direct request or gives a direct instruction to the listener and attaches to the て-form, while 「ように言う」 reports or describes telling someone to do something and attaches to the dictionary form or ない-form. For example, 「寝てください」 is reported as 「寝るように言った」, and the two are not interchangeable.
• なさいN4「なさい」 gives a direct order or instruction, often in a superior-to-subordinate tone, and attaches to the ます-stem, while 「ように言う」 reports telling someone to do something and attaches to the dictionary form or ない-form. 「寝なさいと言った」 can be rephrased as 「寝るように言った」.
• ように/ようなN3「ように/ような」 express comparison, examples, or 'just as...', and can also follow nouns (with 「の」) and adjectives, whereas 「〜ように言う」 attaches only to a verb's dictionary form or ない-form and means 'tell someone to do.' The two are not interchangeable.
• 〜と言うN4「と言う」 quotes what was said, can repeat it word for word, and places no restriction on content, while 「ように言う」 only indirectly reports what someone is told to do or not do. A command can also be reported as 「寝ろと言う」, but this is more direct than 「寝るように言う」.

〜ように言う reports an instruction, whereas てください and なさい are the direct requests or commands themselves, and 〜と言う quotes what someone said. ようにする means making an effort to do something, ようになる means coming to be able to do something or starting to do it, and the N3 ように/ような expresses 'like' or 'as.'