Who reads the report written by professor Grin (Economy sciences, university of Geneva) knows that English-speaking countries have yearly huge profits trough the superiority of his national language in international use. Besides this immense monetary advantages the use of English is an advantage for native English speakers in international discussions and business. This obviously stimulates english speaking countries to promote their own national language, this way endangering the so named "small" languages. Esperanto belongs to none country. It is designed to become everyone's second language and to be used in international communication. There will not be such pressure from any country promoting Esperanto because this language is not their own. Esperanto can be learned by anyone without any need of linguistical submerge in it's owner's country, that even not exists.

One can read the french original report of prof. Grin at http://cisad.adc.education.fr/hcee/documents/rapport_Grin.pdf

http://lingvo.org/raporto_grin_nl.pdf (a translation into dutch) or

http://lingvo.org/raporto_grin_eo.pdf (a translation into Esperanto)

You can find a link to the study of Aron Lukacz at http://www.ekolingvo.com (in many languages).

At least one. Learning the logical "foreign" language will undoubtedly lead to a better knowledge of the own language and is a good help to learn other languages and "logical" subjects such as mathematics and sciences. So Esperanto is the first foreign language to learn. And it is not so "foreign". Most of its lexical elements are immediately understood and its grammar is logical, simple and without exceptions. Therefore, learning it is not discouraging for the children.