The Hebrew used in the Tanakh is often the source for most of Modern Hebrew. However, influences of history have changed the modern day Hebrew in ways that are not always so noticeable. For Example:

A lot of Aramaic has slipped its way into modern Hebrew, even down to the most basic words.

Father in Tanakh: "Av"
Father in Modern Hebrew: "Abba" (Aramaic)

This is not a unique phenomenon, the Tanakh itself has loan words from other languages. If you asked the average Israeli, they would not know that Abba is Aramaic in origin.

The reversing waw/vav is also heavily prevalent in Biblical Hebrew (but by no means is used 100% of the time). It's common English name of the reversing waw/vav is because it switches the past tense to future tense, and future tense to past tense, simply by adding a waw to the front of the verb. You often see a mixing of the normal verb conjugation with a sprinkling of this reversing waw in many paragraphs, including the first paragraph of the Torah.


  בְּרֵאשִׁית, בָּרָא אֱלֹהִים, אֵת הַשָּׁמַיִם, וְאֵת הָאָרֶץ.
  וְהָאָרֶץ, הָיְתָה תֹהוּ וָבֹהוּ, וְחֹשֶׁךְ, עַל פְּנֵי תְהוֹם.
  וְרוּחַ אֱלֹהִים, מְרַחֶפֶת עַל פְּנֵי הַמָּיִם. וַיֹּאמֶר
  אֱלֹהִים, יְהִי אוֹר; וַיְהִי אוֹר; וַיַּרְא אֱלֹהִים אֶת
  הָאוֹר, כִּי טוֹב .וַיַּבְדֵּל אֱלֹהִים, בֵּין הָאוֹר וּבֵין
  הַחֹשֶׁךְ; וַיִּקְרָא אֱלֹהִים לָאוֹר יוֹם, וְלַחֹשֶׁךְ קָרָא
  לָיְלָה. וַיְהִי עֶרֶב וַיְהִי בֹקֶר, יוֹם אֶחָד.


Some other oddities would include the verb roots having changed as Hebrew pronunciation by communities caused mistakes to become the new norm. i can't remember the word off the top of my head, but i remember that the root in the Tanakh had an Ayin, but in modern Hebrew, the Ayin was replaced with an Aleph, most likely due to the pronunciation of Ayin being lost in many communities and the writing reflecting the pronunciation.

Another possible large difference is the use of the "present tense." Modern Hebrew has an established present tense, while according to Historians and Biblical grammarians, Biblical Hebrew has no "present tense." According to them, Biblical Hebrew has only two tenses, perfect tense (action is complete) and imperfect tense (action is not yet complete). For them, words/conjugations that we would call present tense are actually "active participles." An example of what this means/looks like would be the following:


  אָנִי שׁוֹמֵר אוֹתֶךָ
  
  How the text translates in Modern Hebrew: "I am guarding you." 
  
  How the text translates in Biblical Hebrew according to Historians: "I am the
  one that guards you."


But if you try and make the argument of Biblical Hebrew not having a present tense to your local Rabbi, be prepared for some resistance. The prior two times i had mentioned in a Synagogue setting that Biblical Hebrew did not have a present tense, it led to a very long debate in which the Rabbi's would refuse to allow anyone who heard my statement to walk away with the belief that Biblical Hebrew didn't have a present tense.

Is the Hebrew vocabulary used in the Tanakh/(other recognized Hebrew books) the same as the what is considered Hebrew today?
Which sentence is Correct Among both


How much will you pay for me
How you will pay for me

