Code Design – Hardcoding Strings That Will Never Change

So, in my efforts to write a program to conjugate verbs (algorithmically, not through a dataset) for French, I've come across a slight problem.

The algorithm to conjugate the verbs is actually fairly simple for the 17-or-so cases of verbs, and runs on a particular pattern for each case; thus, the conjugation suffixes for these 17 classes are static and will (very likely) not change any time soon. For example:

// Verbs #1 : (model: "chanter")
    terminations = {
        ind_imp: ["ais", "ais", "ait", "ions", "iez", "aient"],
        ind_pre: ["e", "es", "e", "ons", "ez", "ent"],
        ind_fut: ["erai", "eras", "era", "erons", "erez", "eront"],
        participle: ["é", "ant"]
    };

These are inflectional suffixes for the most common class of verb in French.

There are other classes of verbs (irregulars), whose conjugations will also very likely remain static for the next century or two. Since they're irregular, their complete conjugations must be statically included, because they can't reliably be conjugated from a pattern (there are also only [by my count] 32 irregulars). For example:

// "être":
    forms = {
        ind_imp: ["étais", "étais", "était", "étions", "étiez", "étaient"],
        ind_pre: ["suis", "es", "est", "sommes", "êtes", "sont"],
        ind_fut: ["serai", "seras", "sera", "serons", "serez", "seront"],
        participle: ["été", "étant"]
    };

I could put all this into XML or even JSON and deserialize it when it needs to be used, but is there a point? These strings are part of natural language, which does change, but at a slow rate.

My concern is that by doing things the "right" way and deserializing some data source, I've not only complicated the problem which doesn't need to be complicated, but I've also completely back-tracked on the whole goal of the algorithmic approach: to not use a data source! In C#, I could just create a class under namespace Verb.Conjugation (e.g. class Irregular) to house these strings in an enumerated type or something, instead of stuffing them into XML and creating a class IrregularVerbDeserializer.

So the question: is it appropriate to hard-code strings that are very unlikely to change during the lifetime of an application? Of course I can't guarantee 100% that they won't change, but the risk vs cost is almost trivial to weigh in my eyes – hardcoding is the better idea here.

Edit: The proposed duplicate asks how to store a large number of static strings, while my question is when should I hard-code these static strings.