From "The Nursing Mother's Guide to Weaning" by Huggins and Zeidrich, page 125
"Although it has often been said that children usually self-wean between ages
two and four, this isn't borne out by the experiences of women we know.  A few
toddlers do decide to stop nursing... but such behavior is unusual, according
to Ruth Lawrence, author of a leading breastfeeding guide for physicians.
Children rarely initiate weaning between ages one and four, Lawrence says
(1989, 253)"

I don't know if this is what the mom in question was referring to, and don't
know if the age 14 months is specifically mentioned in the book elsewhere.  Of
course, the book is all about weaning, whether planned, baby-led, mother-led,
mutual, abrupt, gradual, or natural - if a mom were to read the entire thing,
she would get a more balanced view than just considering the above quote.

I hope that this helps.
Lisa Jones, LLLL in Wellington FL- 1/2 hr north of Boca Raton