Here is a minimal Codeless Language Module for an hypothetical "Daniel" language that accepts hyphens in keywords.
Save it as Daniel.plist in ~/Library/Application Support/BBEdit/Language Modules.
<?xml version="1.0" encoding="UTF-8"?>
<plist version="1.0">
<dict>
<key>BBEditDocumentType</key>
<string>CodelessLanguageModule</string>
<key>BBLMColorsSyntax</key>
<true/>
<key>BBLMIsCaseSensitive</key>
<false/>
<key>BBLMLanguageCode</key>
<string>Dani</string>
<key>BBLMLanguageDisplayName</key>
<string>Daniel</string>
<key>BBLMSuffixMap</key>
<array>
<dict>
<key>BBLMLanguageSuffix</key>
<string>.daniel</string>
</dict>
</array>
<key>BBLMKeywordList</key>
<array>
<string>step-by-step</string>
<string>Juan-les-Pins</string>
<string>2021-08-24</string>
</array>
<key>Language Features</key>
<dict>