This document discusses models for distinguishing between languages and dialects. It examines the hierarchical family tree model and notes limitations with this approach. Specifically, isoglosses representing different linguistic features do not always align and can intersect, contradicting the assumption in the family tree model that isoglosses should never cross. The document concludes that isoglosses on their own are not sufficient to reliably delimit linguistic varieties, calling into question how to distinguish varieties if not by isoglosses alone.

2. •How clear are the boundaries between
varieties?
Or
•What is the criterion in which adopted
to distinguish between language and
dialect?

3. 1. The hierarchical model of the family
tree implies that the boundaries
between varieties are clear at all
levels of the tree.
2. Is it possible for tree to reveal and
identify even the individual speaker
(idiolect)
3. Mutually intelligible
4. Geographical boundaries.

4. • If we consider the differences based on
geography, it should be identified on
the basis of geographical areas and that
what are called regional dialects .

5. ISOGLOSS
• The dialect geographer may then draw a line
between the area where one item was found
and areas where others were found, showing
a boundary for each area called an ISOGLOSS
(from Greek iso- 'same' and gloss- 'tongue').
• The family tree model allows isoglosses to
make subdivisions within a variety,

6. • According to the family tree model, then,
isoglosses should never intersect. Why?
• for example: One isogloss separates the area (to the
north) where come is pronounced with the same
vowel as stood, from the area where it has the open
vowel [A], as in Received Pronunciation , the prestige
accent of England. The other isogloss separates the
area (to the north-east) where r of farm is not
pronounced, from the area where it is.

7. • Important: The only way to reconcile this kind of
pattern with the family tree model would be to give
priority to one isogloss over the other, but such a
choice would be arbitrary and would in any case
leave the subordinate isoglosses unconnected, each
representing a subdivision of a different variety,
whereas in fact each clearly represents a single
phenomenon.

8. • The conclusion:
I. each item has its own distribution
through the population of speakers,
• II. Reasonable conclusion to draw from the
data. But this leads to the further
that isoglosses need not delimit varieties,
except in the trivial sense where varieties
each consist of just one item; and if we
cannot rely on isoglosses to delimit
varieties, what can we use?