Serious Language Student flashcards offer you the following:

• Users are methodically introduced to 1000+ words of common Chinese vocabulary.

• Progress through the vocabulary is personalized to the user. As the user responds to a flashcard successfully, that card is presented less frequently. If the user needs to review that card, it is presented more frequently. The  formula on which the frequency of card repetition is based flows from research on effective learning curves.

• The Flashcards program lives on the user’s device. One does not need to be connected to the Internet to run the program and practice. One is not affected by the speed of one’s Internet connection. One’s progress is recorded on one’s device, so one is protected from the records ever being “lost in the cloud.”
•  words are introduced:
  first Chinese in 拼音（pīnyīn）to English e.g., gǒu to “dog,”
  then English to Chinese in 拼音（pīnyīn), e.g., “dog” to gǒu,
  then Chinese in 汉字 (hànzì) to 拼音（pīnyīn) and English, e.g., 狗 to gǒu and “dog”, and 
  then English to Chinese, e.g., “dog” to 狗 and gǒu.
• Practice is never multiple choice. Understanding, speaking, and  reading Chinese are not multiple choice tasks. (Do other products use multiple choice?)
• The tone of a Chinese syllable is as important as its initial consonant or its final. 石 (shí) “stone,” 市 (shì) “city” and 矢 (shǐ) “arrow” are as different as “put”, “pet” and “bet” in English. Whenever the Serious Language Student flash cards show 拼音（pīnyīn), the tones are included, and whenever the users write 拼音（pīnyīn), they must include the tones. (Do other products show and require tones?)
• In learning Chinese vocabulary, there is a tension between learning words and learning characters. There are single character words which are rare, but the character is a common component of longer words or is a component of other common characters. The Serious Language Student flash cards balance these two aspects of learning Chinese. The 1,000 words chosen for the Serious Language Student’s flashcards reflect frequency studies of a variety of different corpora. However, certain one syllable words were included, even when their inclusion was not completely justified by their frequency. For example, the radicals that occur in the words used by the Serious Language Student, to the extent that they are themselves words, are included, unless they are extremely uncommon. For example, both 刀 (dāo) “knife” and 禾 (hé) “standing grain” are included, even though they are not particularly common, to facilitate the user’s learning their use as radicals. Similarly, some not very common monosyllabic words are included, because they are used in very common multisyllabic words. Thus, for example, 持 (chí) “to hold, to maintain, to keep,” although not so common, is included to faciliate the learning of such very common words as 支持 (zhīchí) “to support, to back up” and 坚持 (jiānchí) “to persist, to persevere.”
• The Serious Language Student flashcards are designed to make sure that the student not only know characters  passively, i.e. can recognize them, but also actively, i.e., knows them well enough to describe them, which in general means knows them well enough to write them. (Are other products restricted to passive learning of characters?)
• For describing characters the Serious Language Student flashcards use the system that has been standard in China for almost 2,000 years, a system familiar to all literate Chinese and with which every student of Chinese, sooner or later, must become familiar. The specific system used by the Serious Language Student is the one that was standardized in China in the early 1700s, and which is familiar not only  to all Chinese but throughout Asia whereever Chinese characters are known, e.g., Korea, Japan and Viet Nam. More details are provided in the Manual. An example would be that the character 是 (shì), “to be”, is analyzed as having the character for 日 (rì), “sun” on top plus 5 additional strokes below.

• Users can override the order in which  new vocabulary is introduced in order to adapt to the order of vocabulary  introduction of any teacher or textbook. (Do other products have this adaptability?)

• Users can combine a teacher or textbook’s order of introducing new words with the order in which Serious Language Student introduces them by allowing Serious Language Student methodically to expand beyond the teacher or textbook, if the teacher or textbook words are being mastered well.
• Users who are coordinating use of Serious Language Student flashcards with a language course can set Serious Language Student to quiz mode in order to drill a certain set of words with no expansion of vocabulary but staying with the drill of only those words. After the drill or test Serious Language Student can be toggled back to gradual vocabulary expansion. (Do other products have this quiz concentration option.)

• Users can add vocabulary words in addition to the 1000+ words with which Serious Language Student comes supplied. Thus, users working with a teacher or textbook as well as users reading on their own can add to the vocabulary list all the vocabulary introduced by that teacher or textbook or interesting words encountered in reading. Users then practice those added words as part of the Serious Language Student practice. (The ability to add words to the vocabulary corpus appears to be unique to Serious Language Student.)