Splits the sentence into sentence parts based on stopwords.

@param {string} sentence The text to split into sentence parts.
@param {string} language The language for which to split sentences.

@returns {Array} The array with sentence parts.
function splitSentence( sentence, language ) {
	const stopwordRegex = languageVariables[ language ].stopwordRegex;
	const stopwords = sentence.match( stopwordRegex ) || [];
	const splitSentences = splitOnWords( sentence, stopwords );
	return createSentenceParts( splitSentences, language );
}