Haec formula facilis dictu est.

Haec is the nominative singular feminine form of the demonstrative pronoun hic, haec, hoc meaning this.

It is feminine singular because it agrees with formula, which is a feminine singular noun. Since formula is the subject of the sentence, haec is also in the nominative.

So:

• haec = this (feminine singular nominative)
• formula = formula / expression (feminine singular nominative)

Together: haec formula = this formula

Because facilis agrees with formula, which is feminine singular.

The adjective facilis, facile means easy. Its forms include:

• facilis = masculine or feminine nominative singular
• facile = neuter nominative singular

Since formula is feminine, Latin uses facilis.

So:

• formula facilis = an easy formula
• not formula facile, because facile would be neuter

Dictu is the supine in -u of the verb dico, dicere, dixi, dictum (to say, speak).

This is a special verbal form that appears mainly with certain adjectives, especially ones like:

• facilis = easy
• difficilis = difficult
• iucundus = pleasant
• mirabilis = wonderful

In this construction, the -u supine expresses the action with respect to which something is easy, difficult, wonderful, and so on.

So facilis dictu means literally something like:

• easy in respect to saying
• more naturally, easy to say

Because with adjectives like facilis, Latin often uses the supine in -u instead of an infinitive.

So where English says:

• easy to say

Latin very naturally says:

• facilis dictu

This is a standard classical construction. English uses to say; Latin often uses the supine in -u after certain adjectives.

A learner may want to translate word-for-word with an infinitive, but Latin does not always match English structure. Here dictu is the idiomatic choice.

It is a verbal noun-like form, but in practice it behaves as a fixed verbal expression.

The supine is connected to the verb and keeps verbal meaning, but it does not work exactly like a normal infinitive or a normal noun. In facilis dictu, you should mainly recognize the whole phrase as a set pattern:

• facilis dictu = easy to say

So technically it is the supine, but practically it helps to learn it as a common construction used with certain adjectives.

Formula is the subject of the sentence.

The structure is:

• Haec formula = subject
• facilis = predicate adjective describing the subject
• dictu = complement explaining in what respect it is easy
• est = is

So the sentence is built like:

• This formula is easy to say

Because Latin word order is much more flexible than English word order.

Placing est at the end is very normal in Latin, especially in simple statements with a form of to be. Latin often puts the verb last.

So:

• Haec formula facilis dictu est

is perfectly normal Latin word order.

English usually requires:

• This formula is easy to say

But Latin does not need to put est in the second position.

Yes. Latin allows several possible word orders, although some may sound more natural than others depending on emphasis.

For example, these would still make sense:

• Formula haec facilis dictu est
• Facilis dictu haec formula est

The basic relationships stay clear because the endings show the grammar:

• haec matches formula
• facilis matches formula
• est is the verb

Word order in Latin often affects emphasis more than basic meaning.

Yes. This is a well-known Latin pattern.

Latin often uses an adjective plus the supine in -u to mean easy to do, hard to do, wonderful to behold, and so on.

Common examples include:

• facilis dictu = easy to say
• difficilis factu = difficult to do
• mirabile visu = wonderful to see
• foedum auditu = foul to hear

So if you learn facilis dictu, you are also learning a broader grammatical pattern.

It is best not to force it too strictly into English-style active or passive categories.

The phrase facilis dictu means easy to say. In English, that sounds active: someone says it. But the Latin supine here is simply part of a fixed construction after an adjective.

So the safest understanding is:

• dictu tells you the action involved: saying
• facilis dictu means easy with respect to saying, that is, easy to say

You should learn it from the verb dico, dicere, dixi, dictum.

The supine is connected to the fourth principal part, dictum. From that same verb you get:

• dictum = the accusative supine
• dictu = the supine in -u

So if you want to recognize where dictu comes from, look for:

• dico, dicere, dixi, dictum

Yes. Formula is a genuine Latin noun, not just an English word borrowed back into Latin.

In Latin it is a first-declension feminine noun. Depending on context, it can mean things like:

• a form
• a rule
• a set expression
• a formula

So in this sentence it is perfectly normal Latin vocabulary.

Not too literal.

A very literal rendering might be:

• This formula is easy in respect to saying

But that is not good English. The natural translation is:

• This formula is easy to say

That is a good example of an important Latin-reading skill: understand the grammar accurately, but translate idiomatically.