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Advanced Guiraud (AG; Daller, van Hout, & Treffers-Daller, 2003)

How Advanced TTR and Advanced Guiraud work

Daller, van Hout and Treffers-Daller (2003) point out that measures based on frequency lists cannot be applied to those languages for which such detailed frequency lists are unavailable. To address this issue, they propose the use of Advanced TTR (ATTR) and Advanced Guiraud (AG), which can be applied to any language so long as a basic word list is available. ATTR is calculated by simply dividing the number of advanced types that are not in the basic word list by the number of tokens. For AG, the denominator is changed to the square root of the number of tokens. Thus, Daller et al. (2003) did not propose ATTR and AG as more sophisticated lexical richness measures than the LFP (Laufer and Nation, 1995) (including the Beyond 2000 measure; Laufer, 1995) or P_Lex (Meara and Bell, 2001), but instead as simpler measures.

Advanced Guiraud = Advanced Type / √Token
Advanced TTR = Advanced Type / Token

Daller et al. (2003) use these measures along with traditional TTR and the Guiraud index, and compare their effectiveness when applied to the spontaneous speech productions of two Turkish German bilingual groups, one German-dominant and the other Turkish-dominant. Their results show that both ATTR and AG have clear advantages over the traditional measures (TTR and Guiraud). AG, in particular, very clearly differentiated between the two bilingual groups.

References

  • Daller, H., van Hout, R., & Treffers-Daller, J. (2003). Lexical richness in spontaneous speech of bilinguals. Applied Linguistics, 24 (2), 197-222.
  • Laufer, B. (1995). Beyond 2000. A measure of productive lexicon in a second language. In L. Eubank, L. Selinker, & M. Sharwood Smith (Eds.), The current state of interlanguage (Studies in Honor of William E. Rutherford) (pp. 265-272). Amsterdm and Philadelphia, PA: John Benjamins.
  • Laufer, B., & Nation, P. (1995). Vocabulary Size and Use: Lexical Richness in L2 Written Production.　Applied Linguistics, 16 (3), 307-322.
  • Meara, P., & Bell, H. (2001). P_Lex: A simple and effective way of describing the lexical characteristics of short L2 texts. Prospect, 16 (3), 5-19.