I've been writing this for a few hours. It will have mistakes for sure, and you may not understand it. It is not like I discovered a connection between languages, but it is something that may help if you treat this info with caution.
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The thing is that Japanese pitch accent has certain similarities with Spanish accent+intonation. And I tried to clasify Japanes accent pattern comparing them to spanish accent patterns, and it turned out pretty well.

We tend to say that Spanish has not a pitch accent, but a stress accent like English. And this not completely true. Spanish accent has, in some cases, a certain pitch attached to it.

In normal spoken language (spanish) pitch is not that notorious within words alone because tone is generally applied to a whole sentence, but when using the emphatic tone that we use for academic puposes when studying accent, you can see it clearly.

This tone emphasize stress accent with a pitch change, which comes very handy for the purpose of studying japanese pitch.

There are 4 accents in Spanish.
- Agúda -> Stress accent on the last syllable.
- Llana -> Stress accent on the 2nd last syllable.
- Esdrújula -> Stress accent on the 3rd last syllable.
- Sobreesdrújula -> Stress accent on the 4th (or higher) last syllable.

# "Esdrújula" words can be compared more easily, as its pitch is easier to distinguish.

When the "esdrújula" starts on the stress accent, a high tone is maintained through the first 2 syllables, and then falls in the last. High-high-low. They sound similar to ATAMADAKA PATTERN

例　Órdenes, brócoli, técnicas, cómodo.

When the "esdrújula" starts before than the stress accent (word with 4 or more syllables), the tone starts low, it rises when the stress accent hits and stays up, then it falls again in the last syllable. They sound similar to ODAKA PATTERN*

例 Intérprete, tarántula.

# "Sobreesdrújulas" are special words. They appear in two forms when we add certain sufixes.
- Adverbs with "mente" at the end of the word.例　Fácilmente=easily, efectívamente=effectively... [Theese don't have similar pitch accent to japanese so I won't explain more about them].

- Imperative verbs + 2 personal pronoums at the end.
例 Dígamelo=say it to me, véndemelo=sell it to me.

In this case, pitch works same way as it works in "esdrújula" words.

# "Llanas" are the vast majority of words in Spanish.
- When "llanas" words have 3 syllables they start with a low pitch, then on the stress accent they go high, and then go low again on the last one. They sound similar to NAKADAKA PATTERN.
例 Revólver, carácter, abrigo, pantera

- When "llanas" words start on the stress accent (2 syllable words) they go high-low. They sound similar to ATAMADAKA PATTERN.
例 Ángel, éter, frágil.

- When "llanas" have more than 3 syllables, they are not similar to any japanese pitch pattern, BUT, if we say theese words (and also the ones with less syllables) as if they were in a list, their musicality change enough so they become close to HEIBAN PATTERN.

例 Tengo que comprar(I have to buy): tamarindos, naranjas, limones, camisetas, trapos...

(you can pronounce theese lists in different ways, but there is one that fits heiban)

# "Agudas" are the trickiest one. They are almost pitchless, but they can vary in different situations, and all of them are correct in Spanish, so they are not a good example, but they can be similar to some japanese pattern in certain cases.

- When they have 2 syllables, they sound similar to HEIBAN PATTERN.
例 Papá, doblar, genial, jugar. (Similar tone as in こ↑こ).

And that's all I could try to understand for now. I though more things about "agúdas". But they are difficult to match, and they work in very specific sentences. So I don't think is worth to give them time for now.

I have to say this is all made up with Spain's accent in mind. I don't know if it fits on latinamerican accents, but it may work the same.