Slip of the Tongue

A slip of the tongue (Latin lapsus linguae) is an unintended deviation from the form a speaker meant to produce, where the speaker has the target form available and would correct it on noticing. The term covers the full range of speech errors studied in psycholinguistics, from sound exchanges to whole-word substitutions.

Mechanism

Slips arise during the production cascade between message planning and articulation. Victoria Fromkin's Speech Errors as Linguistic Evidence (1973) established that the units that slip — phonemes, syllables, morphemes, words, phrases — match the units posited by linguistic theory, which is the central reason speech errors became a primary data source for models of language production. Garrett's (1975, 1980) two-stage model proposed that errors at different levels (lexical substitutions, sound exchanges, stranding errors) reveal distinct planning frames. Dell's (1986) spreading-activation model treats errors as the natural by-product of parallel activation in a connectionist lexical network: when competing nodes reach similar activation levels, the wrong one occasionally wins.

The major classes of slip are anticipation (the leading list for the reading list), perseveration (black bloxes for black boxes), exchange or spoonerism (you have hissed all my mystery lectures), substitution from a related lexical item (tennis bat for tennis racquet), and blends (shrigged from shrugged + shook). Estimates from corpus studies place the rate at roughly one to two slips per thousand words of running speech.

Slip vs Mistake vs Error

The teaching-relevant distinction comes from Corder (1967) and Edge (1989), covered in Error vs Mistake vs Slip. A slip is a performance lapse: the speaker knows the form, can self-correct on prompting, and the error is unsystematic. A mistake reflects partial competence; an error reflects a competence gap. The psycholinguistic literature uses slip of the tongue in a wider sense than Edge does: any non-pathological production error counts, including those a learner could not self-correct because they involve a target form they have not yet acquired. The two traditions converge on the practical point that slips need acknowledgement rather than treatment.

L2 Production

Slips are more frequent in L2 than in L1 production at every proficiency level below near-native, and the gap narrows but rarely closes. The processing load is higher: the L2 speaker is searching a smaller mental lexicon under more retrieval competition from L1 forms, with less automatised phonological encoding. Common L2 slip types include L1 phonological intrusion (a Vietnamese learner producing /tʃɪp/ for ship under speed), gender or article slips in languages with strong L1 transfer pressure, and morphological stranding where a stem and its inflection separate.

Slips and tip-of-the-tongue states are diagnostically related: a tip-of-the-tongue state often resolves into a slip, with the speaker producing a phonologically similar wrong word ("near miss") rather than the target. Both reveal partial activation in the lexical network.

Relevance to Language Teaching

Treating learner output the same way regardless of slip status is the most common correction error. A learner who says I go yesterday and immediately says went has slipped; intervention in such cases erodes fluency and raises the affective filter without teaching anything. The teacher's diagnostic move is the self-correction prompt: a neutral pause, a quizzical look, or a minimal "again?" gives the learner space to catch the slip themselves. Slips that recur across contexts cease to be slips and become candidates for corrective feedback.

Pronunciation slips deserve separate attention. Where a learner consistently produces an L1-influenced variant under speed, the issue is not a slip but incomplete automatisation of the L2 phonological category. The remedy is fluency-building practice with focused phonological targets, not error correction in real time.

References

• Fromkin, V. A. (Ed.). (1973). Speech Errors as Linguistic Evidence. Mouton.
• Garrett, M. F. (1980). Levels of processing in sentence production. In B. Butterworth (Ed.), Language Production (Vol. 1, pp. 177–220). Academic Press.
• Dell, G. S. (1986). A spreading-activation theory of retrieval in sentence production. Psychological Review, 93(3), 283–321.
• Levelt, W. J. M. (1989). Speaking: From Intention to Articulation. MIT Press.
• Poulisse, N. (1999). Slips of the Tongue: Speech Errors in First and Second Language Production. John Benjamins.