The language of the wise sage, the genius, our teacher Rabbi Yaakov Tzemach, may his light shine, in the introduction to his book Rannu LeYaakov, and these are his words:

לְשׁוֹן הַחָכָם הַגָּאוֹן מָהַרְר״י יַעֲקֹב צֶמַח נֵרוֹ יוֹאִיר בְּהַקְדָּמַת סִפְרוֹ רַנּוּ לְיַעֲקֹב וְזוֹ לְשׁוֹנוֹ

And further it appears to me (וְעוֹד נִרְאֶה לִי), that the revelation of this wisdom now in inferior generations (כִּי גִלּוּי חָכְמָה זֹאת עַתָּה בְּדוֹרוֹת גְּרוּעוֹת), is in order that it be a shield for him now (הוּא כְּדֵי שֶׁיִּהְיֶה לוֹ מָגֵן עַתָּה), to grasp with a whole heart our Father in Heaven (לֶאֱחֹז בְּלֵבָב שָׁלֵם בְּאָבִינוּ שֶׁבַּשָּׁמַיִם), for in those generations most were men of action and pious ones (כִּי בְּאוֹתָן הַדּוֹרוֹת הָרֹב הָיוּ אַנְשֵׁי מַעֲשֶׂה וַחֲסִידִים), and the good deeds would save them from the accusers (וְהַמַּעֲשִׂים טוֹבִים הָיוּ מַצִּילִין אוֹתָן מִפְּנֵי הַמְּקַטְרְגִים). And now we are distant from the supernal root (וְעַתָּה רְחוֹקִים מִשֹּׁרֶשׁ הָעֶלְיוֹן), like the dregs within the barrels (כְּמוֹ הַשְּׁמָרִים בְּתוֹךְ הַחָבִיוֹת), who will protect us (מִי יָגֵן עָלֵינוּ), if not our engagement in this wondrous and profound wisdom (אִם לֹא קְרִיאָתֵינוּ בְּחָכְמָה זֹאת הַנִּפְלָאָה וְהָעֲמוּקָה). And especially according to what the Rav of blessed memory wrote (וּבִפְרָט עַל דֶּרֶךְ שֶׁכָּתַב הָרַב ז״ל), that the hidden matters have now become like revealed ones (שֶׁהַנִּסְתָּרוֹת נַעֲשׂוּ עַתָּה כְּמוֹ נִגְלוֹת), for in this generation immorality rules (כִּי בַּדּוֹר הַזֶּה מוֹשֵׁל הַזְּנוּת), and informing and evil speech (וּמַלְשִׁינוּת וּלְשׁוֹן הָרָע), and hatred in the heart (וְשִׂנְאָה שֶׁבַּלֵּב), and the Klipot have spread (וְנִתְפַּשְּׁטוּ הַקְּלִיפּוֹת), in such a manner that a person is ashamed to conduct himself with words of piety (בְּאוֹפֶן שֶׁמִּתְבַּיֵּשׁ הָאָדָם לִנְהוֹג דִּבְרֵי חֲסִידוּת). And may Hashem protect us (וְה׳ יָגֵן עָלֵינוּ), and forgive our sins (וְיִמְחֹל לַעֲוֹנוֹתֵינוּ), amen so may it be His will (אָכִי״ר), end of his words (עכ״ל).

Another copy from the language of Rabbi Ya‘akov Tzemach in the introduction to his book (עוֹד הַעְתֵּק מִלְּשׁוֹן מַהֲרִי״ץ בְּהַקְדָּמַת סִפְרוֹ), and this is its wording (וְז״ל):

Words that come within the introductions from these discourses (דְּבָרִים הַבָּאִים בְּתוֹךְ הַקְדָּמוֹת מִפִּי דְּרוּשִׁים אֵלּוּ), and these matters are truth and firm (וּדְבָרִים אֵלּוּ אֱמֶת וְיָצִיב), end of his words (עכ״ל): To Rabbi Chaim Vital (לְהָרַח״ו), know (דַּע), that some of our colleagues wrote books for themselves (כִּי קְצָת מֵחֲבֵרֵינוּ כָּתְבוּ לָהֶם סְפָרִים), of what they heard from my master of blessed memory (מַה שֶּׁשָּׁמְעוּ מִמּוֹרִי זלה״ה), and from others in his name (וְזוּלָתוֹ עַל שְׁמוֹ), and all of them wrote the matters with addition and subtraction (וְכֻלָּם כָּתְבוּ הַדְּבָרִים בְּתוֹסֶפֶת וְגִרְעוֹן), according to the aspect of the writers and their knowledge (כְּפִי בְּחִינַת הַכּוֹתְבִים וִידִיעָתָם), and in their understanding (וּבַהֲבָנָתָם), they left room for many difficulties (הִנִּיחוּ מָקוֹם לְכַמָּה קֻשְׁיוֹת), therefore one must not rely on those books (לָכֵן אֵין לִסְמוֹךְ עַל אוֹתָן הַסְּפָרִים), and one must distance from them (וְצָרִיךְ לְהַרְחִיק מֵהֶם). And know (וְדַע), that everything I have written here (כִּי כָּל מַה שֶּׁכָּתַבְתִּי כָּאן), I heard from my master of blessed memory (הַכֹּל שָׁמַעְתִּי מִמּוֹרִי זלה״ה), therefore I wrote everything in one composition alone (לָכֵן כָּתַבְתִּי הַכֹּל בְּחִבּוּר אֶחָד לְבַד). And what I heard from the colleagues in the name of my master of blessed memory (וּמַה שֶּׁשָּׁמַעְתִּי מֵהַחֲבֵרִים מִשֵּׁם מוֹרִי זלה״ה), what he expounded and revealed to them before I studied with him (מַה שֶּׁדָּרַשׁ וְגִלָּה לָהֶם קֹדֶם שֶׁלָּמַדְתִּי עִמּוֹ), I wrote that also separately (הַכֹּל כָּתַבְתִּי גַּם כֵּן לְבַדּוֹ), and upon it they said, from the mouth of my master of blessed memory (וְעָלָיו אָמְרוּ מִפִּי מוֹרִי זלה״ה).