(_b_) Esperanto: 3 forms.

Turning to the passive voice, we get—

(_a_) Latin: A complete set of different endings, some of them puzzling
in form and liable to confusion with other parts of the verb.

(_b_) Esperanto: No new endings at all. Merely the three-form regular
active conjugation of the verb _esti_ = to be, with a passive participle.
No confusion possible.

It is just the same with compound tenses, subjunctives, participles,
etc. Making all due allowances, it is quite safe to say that the Latin
verb is fifty times as hard as the Esperanto verb.

The proportion would be about the same in the case of substantives,
Latin having innumerable types.

Comparing modern languages with Esperanto, the proportion in favour of
the latter would not be so high as fifty to one in the inflection of
verbs and nouns, though even here it would be very great, allowing for
subjunctives, auxiliaries, irregularities, etc. But taking the whole
languages, it might well rise to ten to one.

For what are the chief difficulties in language-learning?

They are mainly either difficulties of phonetics, or of structure and
vocabulary.