You can learn to speak a language efficiently through learning sentences.
One of many methods of language acquisition is learning a large number of sentences, through which you internalise the grammar of a language by assimilating sentence patterns. This enables you to get a feel for how to speak correctly in your new language.
Use the language pairs to learn sentences through a language that you already know.
The above are professionally translated with audio.
These additional sentences, are sentences that I have come across when speaking the languages that I am learning and are more idiosynchratic and often more colloquial. These are not the type of sentences that you are likely to find in a phrasebook.
The number of sentences often quoted to arrive at fluency is 10,000, but the number is arbitrary. The more you sentences you learn the better, and the faster you will improve.
Surface Languages contains at least 500 sentences in each of the languages covered, using the basic vocabulary needed for day to day conversations. These are learnt and tested using flashcards combined with a spaced repitition system.
Here are a few pointers to get the most out of sentence based learning.
1. Do other things. Don't just rely on learning sentences in isolation.
2. It is extremely helpful to understand how a sentence fits together - i.e. the grammar of the sentence.
3. The sentences on Surface Languages increase in complexity.
4. Languages themselves are structured differently, meaning you can’t pick one sentence to illustrate a grammatical point in say Spanish and assume that this will illustrate the same point in Polish. However, if you learn enough sentences all the grammar of a language will be covered.
The sentences chosen are ones used in normal life and day to day living, and not specifically to illustrate structures and grammar.
5. The next observation is that many languages have different levels of formality depending on who you are speaking to, and different structures depending on the number of people you are speaking to.
The solution taken here is to assume that you are talking to one person who is a friend.
6. In some languages (e.g. Polish) there can be a difference depending on whether a man or woman is speaking, or being spoken to.
These sentences assume a man is speaking to a man but in general the differences are minor, and it is beyond the scope of this site to go into this level of detail.
7. Another fact to be aware of is that there may be more than one way to translate a phrase with the same meaning in English but more than one way of saying it in another language.An example from Spanish illustrates this. 'It is raining' may be translated as llueve or esta llovendo whereas in English 'it is raining' can only be translated in one way.
The Spanish used depends on the context.
Solution. You can't rely solely on learning sentences in isolation but need to use additional materials.
8. A sentence may have more than one translation into English.
For example, W styczniu byliśmy dwa tygodnie w górach is literally translated as 'In January we were in the mountains for two weeks'.
This could equally well be expressed in English as 'In January we had two weeks in the mountains' or 'In January we spent two weeks in the mountains'.
Solution. As above. Use additional materials so that you understand how the sentences are structured. The translations are matched on the English.
The idea behind massive sentence learning is described here in more detail, but the basic idea is the more sentences that you learn the better. Personally, I think that after one thousand or so, you are better off talking, and if you still want to learn sentences, then learning only sentences that are specific to you.