Do ESPs penalize accented vowels for spam?

Question

I'm using a mailing platform which provides a spam score/meter.

When testing a subject line with an accented vowel such as "envía", the spam meter alerts that I'm using special characters which increases the chances my mail goes to the spam folder.

This platform has awful support for any language other than english and I'm wondering if it just be that or if accented characters are really penalized.

Answer 1

It depends on the particular spam filter and how it's configured. Some filters do, or can be configured to, penalize accented characters (non-ASCII characters in general), but not so much so that it will automatically hit the spam threshold.

Since the filters are on the clients' end and you have no control over it, I would recommend not worrying about it too much. If your emails genuinely are not spam, they should get through fine. If they don't, chances are the client has an overly aggressive filter and there's not a lot you can do about it.

The reason non-ASCII characters might be penalized is that spammers often use them to disguise keywords. For example, "viagra" could be spelled with an accented í as "víagra"; this would circumvent a naive filter programmed to penalize emails containing the word "viagra." I don't know this for certain, but I would imagine the more advanced filters are smart enough to heuristically distinguish this type of usage from genuine human language using accented characters.