Beginner learners of Hebrew might expect a more 1:1 ratio of English words for their translation, but they are unaware of many of the facts with regard to Hebrew word construction and grammar. Let us consider but a few of these.
Parts of a Hebrew Word
A Hebrew word joins what English would often separate into separate words. For example, "in the beginning" in English is all one word in Hebrew: "be-reshit" (literally "in beginning" as in Hebrew there is no need for the definite article here). Prepositions can sometimes stand alone, but usually they are joined to their object, the noun. A conjunction is also joined to the word it is joining, as is the definite article, if it is used. So one "word," delimited by spaces as are English words, will actually consist of multiple grammatical units. This can be seen in the notations of a good interlinear which shows the grammar.
Consider the following example.

Each "|" in the grammatical notations indicates what we might consider a separate word. The last word of the verse, "לְמָֽעְלָה׃", translated as "exceedingly" in the interlinear, is actually from three grammatical units in Hebrew: the initial lamed "לְ" being a preposition meaning "to" or "for", followed by the root word which means "higher part" or "above", to which is added a pronominal suffix (a pronoun) which makes the whole word third-person feminine singular (like "she" or "her")--a point which may indicate agreement with the gender of what it is modifying, or may have nothing at all to do with the gender of what it modifies and more to do with its grammatical purpose (for example, numbers are usually feminine in Hebrew).
The word just before this also shows division into three sub-units, which are actually four: the "וַֽ" representing a conjunction, usually translated as "and" but which might contextually represent "so", "therefore", "thus", or even "but"; the rest of the word "יְגַדְּלֵ֖הוּ" representing the verb which already contains its pronoun and to which is added a pronominal suffix indicating third-person masculine singular ("he" or "him"--or, because Hebrew does not have a separate form for "it", this could also be "it").
Hebrew Verbs
A full treatise on Hebrew verbs might occupy several books in the making; but for purposes of this answer, a few details will suffice to bring more clarity.
Hebrew verbs always contain the person (1st-, 2nd-, or 3rd-person) and number (singular or plural) of the subject, and may also contain a pronominal suffix bearing this same information for the object. In Hebrew, verbs precede their subject in the typical sentence order, and because their subject's pronoun is already embedded, the subject itself is not always required to be specified separately (unlike English).
For example: "bereshit bara Elohim" in Genesis 1:1 would literally translate as "in beginning he-created God" which would be restructured in English as "in the beginning, God, he created." The added pronominal information of the verb is usually dropped in English when it is redundant, as in this case, since the "he" just refers to "God"--so we would say "in the beginning God created..." But even with those five words in English, there is still more meaning that was packed into the three words of Hebrew than English reveals. For example, "bara", the verb, is only used for God throughout the Old Testament. If someone else creates something, a different verb will be used--unlike English where "create" is used for both God and anyone else.
Hebrew verbs are divided up into "binyanim" (verb forms)--of which there are as many as 490 forms for a single verb; but scholars tend to shy away from calling these "tenses." This is because Hebrew verbs do not indicate past, present, and future as English verb tenses do. Hebrew verbs may indicate a transpiring action (imperfect) versus a completed action or simple fact (perfect). They have modal forms (like "can", "may", "should", etc.) which some might term "subjunctive" in usage, but Hebrew grammarians will subdivide these by their persons into cohortative, imperative, or jussive forms. An English verb might have multiple words to express it, such as "should have been accompanying" (modal perfect continuous tense); whereas a verb like that would be expressed as a single word in Hebrew.
The spelling of the word, particularly its vowel pointings, determines its form. This brings us to another important point.
Hebrew Word Spellings
Written Hebrew did not originally have vowels. The earliest vowels began to creep into the writing hundreds of years after the Pentateuch was written, but even these were few. Vowel pointings were not added until the Masoretes did so between about A.D. 500 and A.D. 1100. So each Hebrew word is more "compact" than an English word would be. In the original, vowels occupied no space at all, and modern manuscripts have the pointings above and below each consonant, still not requiring much, if any, horizontal space.
Construct Chains versus Predicate Adjectives
Hebrew does not need to add a preposition between two consecutive nouns, or a verb of being between those nouns, where in English our grammar would require this. In Hebrew, if both nouns are definite or if both are *not definite, then they have equal definiteness. If they are equal, they form a "construct chain." In this case, they are placed in genitive relationship, usually indicated by the use of "of" in English.
For example, "face deep" in Genesis 1:2 must have the "of" added as well as the articles to become "the face of the deep" because both "face" and "deep"--two consecutive nouns--are in their common, non-definite forms. If we were to make one of these nouns definite by adding the definite article ("the") so that they were no longer equal in definiteness, then they would be placed together in a predicate adjective relationship, implying a verb of being; e.g. "the face deep" would be translated as "the face is deep." These verbs of being and prepositions showing relationship of nouns are unnecessary in Hebrew grammar, but are required in the English translation.
Nuance
It is common that during translation words with a particular nuance in their original language require multiple words in the target language to convey the same meaning. If a word does not happen to have even a close equivalent in the target language, sometimes an entire phrase may be needed to describe it. In English, for one example, the word "love" might be considered a word with broad meaning, as compared with Greek which has many words for love. If a translator desires to distinguish between "agape" love and "eros" (romantic/lust), or "philia" (friendship), or "storge" (family), or "mania" (obsession), or "philautia" (self-love), how can he or she do so without the addition of some modifier or explanation?
Nuance is either lost, or maintained through the addition of words; and translations from almost any language tend to result in a greater amount of text in their target (translated) language.
Conclusion
Hebrew ranks among the most complex of languages in the world. Overall, Hebrew "words" are far more compact than English words, and contain multiple words-worth of information. Only the Hebrew direct-object-marker word "et" is typically untranslated/unnecessary in English. Most Hebrew words will naturally require multiple words in English to properly render their meaning.