The letter ה represents the traditional phoneme /h/ (like the sound of ⟨h⟩ in the English word hat). In present-day Israeli Hebrew, this phoneme is generally dropped in ordinary speech — a word such as הֵם(hém, “them”) is usually pronounced /em/, at least in everyday conversation — but the letter ה is still used where the sound /h/ would be expected, such as in loanwords where the source word has /h/.
The letter ה is also used as a silent letter (a mater lectionis) at the end of a word, to indicate the presence of a vowel that is not otherwise indicated. This vowel is usually /a/ (as in יַלְדָּה(yaldá) and סֶלָה(séla)), but often /e/ (as in אֵלֶּה(éle) and תֵּה(té)), and in a few cases /o/ (as in כֹּה(kó)). However, final vowels are not necessarily indicated by any letter at all; for example, the words לְךָ(l'khá), אָמַרְתָּ(amárta), and אֵלֶיהָ(eléha) all end with a vowel /a/ that is not indicated by a following letter. Conversely, this silent use of ה appears, in a very small number of exceptional cases, in the interior of a word, such as in יְפֵהפֶה(y'fefé).
In writing with vowels, when a letter ה representing the phoneme /h/ occurs at the end of a word, it is written with dot inside, called a mapík, to distinguish it from the silent use: לָהּ(láh), גובה \ גֹּבַהּ(góvah). In nowadays speech, this /h/ is usually not pronounced.
Like the letters א, ח, ע, and ר, the letter ה never takes a dagésh (that is: in Tiberian /Masoretic Hebrew, which distinguished consonant length, the phoneme /h/ lost the ability to geminate gemination), and in circumstances where a dagésh would otherwise be expected, there is frequently lengthening in the preceding vowel vowel to compensate for the loss of gemination. Vowel length and consonant length (gemination) is absent from Modern Hebrew. For example, the infinitive of נֶהֱרַג(neherág) is לְהֵהָרֵג(l'hêhārég) rather than *לְהִהָּרֵג(l'hihhārég).
Like the letters א, ח, and ע, the letter ה generally does not take a sh'vá (be it a sh'vá ná or a sh'vá nákh); rather, it takes a khatáf vowel: הֲלִיכָה(halikhá), נֶהֱרַס(neherás), צהריים \ צָהֳרָיִם(tsohoráyim). Additionally, like word-final ח and ע, a word-final non-silent ה takes a patákh g'nuvá after any vowel other than /a/: גבוה \ גָּבֹהַּ(gavóah).
Since ה is used as a silent letter at the end of a word, it also is traditionally used as a placeholder in the representation of consonantal roots that have a sort of “gap” at the end. For example, the roots of the verbs קָנָה(kaná), נִרְאָה(nir'á), הִרְשָׁה(hirshá), חיכה \ חִכָּה(khiká), and הִתְגַּלָּה(hitgalá) are ק־נ־ה(k-n-), ר־א־ה(r-'-), ר־שׁ־ה(r-sh-), ח־כ־ה(kh-k-), and ג־ל־ה(g-l-), respectively. In some forms, this “gap” becomes ת/t/ (as in קָנְתָה(kan'tá)); in others, it becomes י/j/ (as in גילוי \ גִּלּוּי(gilúi)); in others, it becomes a silent א (as in הַרְשָׁאָה(harsha'á)); and in others, it essentially disappears (as in נִרְאוֹת(nir'ót)).
For information about ה as a prefix meaning roughly “the”, marking a noun or adjective as definite, see ה־.
For information about ה prepended to the first word of a yes-or-no question, see ה־.
For information about ה as a suffix meaning roughly “-ward”, marking a noun as an adverbial destination, see ־ה.
For information about ה as a suffix meaning roughly “her”, which is one form of the third-person feminine singular personal pronoun, see ־הּ.
For information about ה as a general feminine suffix on nouns, adjectives, and verb forms, see ־ה.
For information about ה as a sort of prefix in the past tense, infinitive forms, and/or action nouns of hif'íl, huf'ál, hitpa'él, and nif'ál verbs, see Appendix:Hebrew verbs.
