我聽說,如果沒在十二歲前開始學一個語言,是無法達到母語等級的。

I've heard it said that there is no way for you to ever reach native proficiency in a language if you haven't started studying it before the age of twelve.

Source: Tatoeba

Sentence Composition

1
  1. I
  2. me
  3. my
2 聽說 tīngshuō
  1. to hear (sth said)
  2. one hears (that)
  3. hearsay
  4. listening and speaking
3 如果 guǒ
  1. if
  2. in case
  3. in the event that
=4 méi (negative prefix for verbs) have not; not
=4
  1. drowned
  2. to end
  3. to die
  4. to inundate
5 zài
  1. to exist; to be alive
  2. (of sb or sth) to be (located) at
  3. (used before a verb to indicate an action in progress)
=6 十二 shíèr
  1. twelve
  2. 12
=6 十二 shí'èr twelve; 12
7 suì
  1. classifier for years (of age)
  2. year
  3. year (of crop harvests)
8 qián
  1. front
  2. forward
  3. ahead
  4. first
  5. top (followed by a number)
  6. future
  7. ago
  8. before
  9. BC (e.g. 293)
  10. former
  11. formerly
9 開始 kāishǐ
  1. to begin
  2. beginning
  3. to start
  4. initial

classifier:

10 xué
  1. to learn
  2. to study
  3. to imitate
  4. science
  5. -ology
=11 一個 ge
  1. a; an; one
  2. the whole (afternoon, summer vacation etc)
=11 一個
  1. Combination of the numeral (“one”) and the generic classifier : a; an; one
  2. same
=12 語言 yán language

classifiers: ,

=12 語言 yán
  1. (literary) to tell
  2. to tell
=13 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=13 shì variant of shì
14 無法 unable to; incapable of
15 達到 dào to reach; to achieve; to attain
16 母語
  1. native language
  2. mother tongue
  3. (linguistics) parent language
17 等級 děng
  1. grade
  2. rank
  3. status
=18 de
  1. of; ~'s (possessive particle)
  2. (used after an attribute when it modifies a noun)
  3. (used at the end of a declarative sentence for emphasis)
  4. (used after a noun, verb or adjective to form a nominal expression, as in 皮革的 de "one made of leather" or 跑堂儿的 pǎotángrde "a waiter (literally, one who runs back and forth in a restaurant)" or 新的 xīnde "new one")
  5. also pr. or di in poetry and songs
=18 a taxi; a cab (abbr. for 的士 shì)
=18 really and truly
=18 (bound form) bull's-eye; target