mathematics

Linguistic diversity index

Linguistic diversity index is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Linguistic diversity index rather than just read about it. In short: Linguistic diversity index (LDI) may refer to either Greenberg's (language) Diversity Index or the related Index of Linguistic Diversity (ILD) from Terralingua, which measures changes in the underlying LDI over time. Greenberg's Diversity Index (LDI) is the probability that two people selected from the population at random will have different mother tongues; it therefore ranges from 0 (everyone has the same mother t…

Key takeaways

Linguistic diversity index belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Linguistic diversity index to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Linguistic diversity index from memory before moving on to harder problems.

Reference excerpt

Linguistic diversity index (LDI) may refer to either Greenberg's (language) Diversity Index or the related Index of Linguistic Diversity (ILD) from Terralingua, which measures changes in the underlying LDI over time. Greenberg's Diversity Index (LDI) is the probability that two people selected from the population at random will have different mother tongues; it therefore ranges from 0 (everyone has the same mother tongue) to 1 (no two people have the same mother tongue). The ILD measures how the LDI has changed over time; a global ILD of 0.8 indicates a 20% loss of diversity since 1970, but ratios above 1 are possible, and have appeared in regional indexes. The computation of the diversity index is based on the population of each language as a proportion of the total population. The index cannot fully account for the vitality of languages. Also, the distinction between a language and a dialect is fluid and often political. A great number of languages are considered to be dialects of another language by some experts and separate languages by others. The index does not consider how different the languages are from each other, nor does it account for second language usage; it considers only the total number of distinct languages, and their relative frequency as mother tongues.

Rankings by country The UNESCO report cites an earlier (2005) edition of the Ethnologue as its own source for this particular data. The UNESCO report remains a useful independent source and benchmark year because of its wider availability. Footnotes do warn that the precise numbers should be used with some skepticism.

See also Ethnologue Linguistic rights List of official languages by country and territory List of countries by number of languages Cultural diversity

Notes and references

Notes

References

External links Terralingua's Index of Language Diversity is a dead link, but similar information is available from the same site at https://web.archive.org/web/20120822015417/http://www.terralingua.org/linguisticdiversity/ and it appears to be based on the following paper: http://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/4474/harmonloh.pdf

Illustrations

Worked examples

Example 1 — a first encounter with Linguistic diversity index

Start with the simplest possible case. Write down what Linguistic diversity index claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Linguistic diversity index before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Linguistic diversity index ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Linguistic diversity index

In research: Linguistic diversity index appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Linguistic diversity index in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Linguistic diversity index is common in secondary-school and first-year university syllabi. It links to neighbouring topics Applied linguistics, Index numbers, Language geography, so understanding it makes those chapters shorter.
In everyday life: Look for Linguistic diversity index outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Linguistic diversity index in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Linguistic diversity index means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Linguistic diversity index out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Linguistic diversity index in simple terms?

Why does Linguistic diversity index matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Linguistic diversity index?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Linguistic diversity index.