Some students understand this idea intuitively. For those who don't, I have a crucial message: Don't fight the language! It took centuries for the language to develop and it's not going to change just because you feel more comfortable expressing something in a way that is more similar to your native tongue.
So if you hear a native speaker say something a certain way, assume that that is the only way to express it until you hear otherwise from another native speaker. I always tell students that language is not like mathematics. Language is rarely 100% logical. It's often messy; sometimes flexible, sometimes not. At the end of the day, it is what it is. And that goes not only for semantics, but also for syntax, grammar and phonology. The goal should be to accept it readily and repeat it. Use newly acquired expressions frequently at first, just as a parrot would repeat phrases it learns, and then remain open and ready for the next expression to come your way.
If a native speaker says he's 64, that means he's 64 years old. Note that the verb to be is used to express someone's age. Your language may use another verb, such as have. Don't force your language onto English. If you say he has 64 years, a literal translation from many Latin-based languages, you're going to sound very odd and may not be understood. By the way, did you catch the other detail? In English, it is not necessary to say years to express someone's age. But if you do, you need to say years old, not simply years. There's a prime example of staying open and attentive to every detail.
While it's important to pay attention to the details, there simply isn't enough time to question every little detail. When students get hung up on the way the foreign language expresses something, they miss the next opportunity to learn more of the language. So, stay open, listen carefully and be a parrot! That's how successful language learners do it.
It helps to think of language as short segments or phrases, not so much individual words. Treat these phrases like gold nuggets that you mine from your foreign-language conversational partner. Each is precious and should be stowed away to be used later; hopefully soon afterward, so that you can solidify it in your memory.
When learning English, in particular, watch for how the verbs are used with particles. These particles look like prepositions, but they're not. They are there to transform the meaning of the main verb. We call these phrasal verbs, or two-part or three-part verbs. And always learn a new word or phrase noting the context in which it was used.
The creation of new vocabulary, and the change in meaning of vocabulary and phrases between languages that historically have a common root, happens in part as a result of the cultural needs of the population that uses the language. Eskimos, for instance, have numerous ways to express different types of ice. They need to be able to express ice in its various forms in order to survive in that climate. But it goes beyond mere survival. When you see something every day, you begin to notice the intricacies of it and that leads to the desire to more accurately define and express it. For most of us who live in warmer climes, a handful of words to describe ice suffices. But for the Inuit of Canada, who appreciate ice to a much larger degree than we do, discerning the many differences in the quality of ice has led to the creation of more than 53 words for it. And in the northern parts of Scandinavia and Russia, the Sami people use around 180 words related to ice and snow!
You can think of the meaning of words as overlapping circles. In the image that follows, each circle represents the meaning of one word. The space in between the circles represents an aspect of reality that has not been defined by the language. Interestingly enough, when a language doesn't define something, the undefined reality often goes unperceived by the speaker of that language.