Interlanguage and Fossilization

The concept of interlanguage and fossilization are important for language teachers and learners alike.

For teachers, understanding interlanguage and fossilization can help them to better understand the language development process and to provide appropriate instruction and feedback to their students.

For learners, understanding interlanguage and fossilization can help them set realistic goals for their language acquisition and to understand why they may be having difficulty with certain aspects of the target language.

Let’s understand what these two terms fully mean.


Interlanguage is the term for a dynamic linguistic system that has been developed by a learner of a second language (or L2) who has not become fully proficient yet but is approximating the target language: preserving some features of their first language (or L1), or overgeneralizing target language rules in speaking or writing the target language and creating innovations.

Interlanguage work is a vibrant microcosm of linguistics. It is possible to apply an interlanguage perspective to learners’ underlying knowledge of the target language sound system (interlanguage phonology), grammar (morphology and syntax), vocabulary (lexicon), and language-use norms found among learners (interlanguage pragmatics).


Fossilization is the ‘freezing’ of the transition between the native language and the target language.

Fossilization occurs when an L2 learner is capable of conveying a message with current language knowledge, therefore the need to correct the form/structure is not required. Thus, the learner fossilizes the form instead of correcting it.

Fossilization can happen at different levels of language learning, including:

#1Phonological (pronunciation)
#2Grammatical (syntax and morphology)
#3Lexical (vocabulary).

Factors that Contribute to Fossilization

Several factors contribute to the occurrence of fossilization:

  • Age of Acquisition: Fossilization is more common among learners who begin acquiring a second language later in life, particularly after the critical period for language acquisition (usually around puberty).
  • Input Quality and Quantity: The quality and quantity of exposure to the target language play a significant role. Learners who have limited or poor-quality input may be more prone to fossilization because they have fewer opportunities to encounter and internalize correct language forms.
  • Motivation and Attitude: Learners with a strong motivation to improve and a positive attitude toward language learning are more likely to persist in correcting their errors and avoiding fossilization. On the other hand, disinterest or frustration can contribute to fossilization.
  • Individual Learning Strategies: Learners may develop different strategies for acquiring a second language. Some may focus more on fluency and communication, while others prioritize accuracy. Those who prioritize fluency might be more prone to fossilization of certain errors.
  • Lack of Corrective Feedback: Consistent and timely corrective feedback from teachers, peers, or native speakers is crucial for avoiding fossilization. If learners do not receive effective feedback on their errors, they may continue to use incorrect forms.
  • Learner’s Awareness and Self-Correction: Learners who are more aware of their errors and actively engage in self-correction are less likely to fossilize those errors
  • Complexity of Language Features: Some language features may be more prone to fossilization than others. Complex grammatical structures or pronunciation patterns may be more difficult to correct and, therefore, more likely to become fossilized.

Errors Caused by the First Language

Fossilized errors are usually made because of the influence of the mother tongue. 

These are some common mistakes students whose first language is Spanish tend to make unless they are corrected

  • “I have 20 years old ( Learners use the verb to have instead of the verb to be)
  • “Do you know where is she?” (Learner doesn’t know how to make embedded questions)
  • “She is long hair” ( Learner uses the verb to be instead of the verb to have)
  • “I have a cat black” (Learner maintains the word order from one’s native language)
  • “I don’t know nothing” (Learner uses using double negatives in a language that doesn’t require them)
  • “I have car” (Learner omits article)

More English Teaching Article

Did you find this interlanguage and fossilization article useful?

These are some English teaching articles that you might want to check before you leave

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  2. 14 Essential Characteristics of a Good Language Learner
  3. The Monitor Hypothesis in Second Language Acquisition
  4. 10 Characteristics of Student-Centered Learning
  5. ESL Classroom Activities: Dictogloss
  6. 10 Types of Teachers: Which One are You?
  7. How to Teach Collocations in English

Manuel Campos, English Professor

Manuel Campos

I am Jose Manuel, English professor and creator of, a blog whose mission is to share lessons for those who want to learn and improve their English