The locale indicated by the
      lc_time_names system variable
      controls the language used to display day and month names and
      abbreviations. This variable affects the output from the
      DATE_FORMAT(),
      DAYNAME(), and
      MONTHNAME() functions.
    
      lc_time_names does not affect the
      STR_TO_DATE() or
      GET_FORMAT() function.
    
      The lc_time_names value does not
      affect the result from FORMAT(),
      but this function takes an optional third parameter that enables a
      locale to be specified to be used for the result number's decimal
      point, thousands separator, and grouping between separators.
      Permissible locale values are the same as the legal values for the
      lc_time_names system variable.
    
      Locale names have language and region subtags listed by IANA
      (http://www.iana.org/assignments/language-subtag-registry)
      such as 'ja_JP' or 'pt_BR'.
      The default value is 'en_US' regardless of your
      system's locale setting, but you can set the value at server
      startup, or set the GLOBAL value at runtime if
      you have privileges sufficient to set global system variables; see
      Section 7.1.9.1, “System Variable Privileges”. Any client can
      examine the value of
      lc_time_names or set its
      SESSION value to affect the locale for its own
      connection.
    
      (The first SET NAMES statement in
      the following example may not be necessary if no settings relating
      to character set and collation have been changed from their
      defaults; we include it for completeness.)
    
mysql> SET NAMES 'utf8mb4';
Query OK, 0 rows affected (0.09 sec)
mysql> SELECT @@lc_time_names;
+-----------------+
| @@lc_time_names |
+-----------------+
| en_US           |
+-----------------+
1 row in set (0.00 sec)
mysql> SELECT DAYNAME('2020-01-01'), MONTHNAME('2020-01-01');
+-----------------------+-------------------------+
| DAYNAME('2020-01-01') | MONTHNAME('2020-01-01') |
+-----------------------+-------------------------+
| Wednesday             | January                 |
+-----------------------+-------------------------+
1 row in set (0.00 sec)
mysql> SELECT DATE_FORMAT('2020-01-01','%W %a %M %b');
+-----------------------------------------+
| DATE_FORMAT('2020-01-01','%W %a %M %b') |
+-----------------------------------------+
| Wednesday Wed January Jan               |
+-----------------------------------------+
1 row in set (0.00 sec)
mysql> SET lc_time_names = 'es_MX';
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT @@lc_time_names;
+-----------------+
| @@lc_time_names |
+-----------------+
| es_MX           |
+-----------------+
1 row in set (0.00 sec)
mysql> SELECT DAYNAME('2020-01-01'), MONTHNAME('2020-01-01');
+-----------------------+-------------------------+
| DAYNAME('2020-01-01') | MONTHNAME('2020-01-01') |
+-----------------------+-------------------------+
| miércoles             | enero                   |
+-----------------------+-------------------------+
1 row in set (0.00 sec)
mysql> SELECT DATE_FORMAT('2020-01-01','%W %a %M %b');
+-----------------------------------------+
| DATE_FORMAT('2020-01-01','%W %a %M %b') |
+-----------------------------------------+
| miércoles mié enero ene                 |
+-----------------------------------------+
1 row in set (0.00 sec)
      The day or month name for each of the affected functions is
      converted from utf8mb4 to the character set
      indicated by the
      character_set_connection system
      variable.
    
      lc_time_names may be set to any
      of the following locale values. The set of locales supported by
      MySQL may differ from those supported by your operating system.
| Locale Value | Meaning | 
|---|---|
| ar_AE | Arabic - United Arab Emirates | 
| ar_BH | Arabic - Bahrain | 
| ar_DZ | Arabic - Algeria | 
| ar_EG | Arabic - Egypt | 
| ar_IN | Arabic - India | 
| ar_IQ | Arabic - Iraq | 
| ar_JO | Arabic - Jordan | 
| ar_KW | Arabic - Kuwait | 
| ar_LB | Arabic - Lebanon | 
| ar_LY | Arabic - Libya | 
| ar_MA | Arabic - Morocco | 
| ar_OM | Arabic - Oman | 
| ar_QA | Arabic - Qatar | 
| ar_SA | Arabic - Saudi Arabia | 
| ar_SD | Arabic - Sudan | 
| ar_SY | Arabic - Syria | 
| ar_TN | Arabic - Tunisia | 
| ar_YE | Arabic - Yemen | 
| be_BY | Belarusian - Belarus | 
| bg_BG | Bulgarian - Bulgaria | 
| ca_ES | Catalan - Spain | 
| cs_CZ | Czech - Czech Republic | 
| da_DK | Danish - Denmark | 
| de_AT | German - Austria | 
| de_BE | German - Belgium | 
| de_CH | German - Switzerland | 
| de_DE | German - Germany | 
| de_LU | German - Luxembourg | 
| el_GR | Greek - Greece | 
| en_AU | English - Australia | 
| en_CA | English - Canada | 
| en_GB | English - United Kingdom | 
| en_IN | English - India | 
| en_NZ | English - New Zealand | 
| en_PH | English - Philippines | 
| en_US | English - United States | 
| en_ZA | English - South Africa | 
| en_ZW | English - Zimbabwe | 
| es_AR | Spanish - Argentina | 
| es_BO | Spanish - Bolivia | 
| es_CL | Spanish - Chile | 
| es_CO | Spanish - Colombia | 
| es_CR | Spanish - Costa Rica | 
| es_DO | Spanish - Dominican Republic | 
| es_EC | Spanish - Ecuador | 
| es_ES | Spanish - Spain | 
| es_GT | Spanish - Guatemala | 
| es_HN | Spanish - Honduras | 
| es_MX | Spanish - Mexico | 
| es_NI | Spanish - Nicaragua | 
| es_PA | Spanish - Panama | 
| es_PE | Spanish - Peru | 
| es_PR | Spanish - Puerto Rico | 
| es_PY | Spanish - Paraguay | 
| es_SV | Spanish - El Salvador | 
| es_US | Spanish - United States | 
| es_UY | Spanish - Uruguay | 
| es_VE | Spanish - Venezuela | 
| et_EE | Estonian - Estonia | 
| eu_ES | Basque - Spain | 
| fi_FI | Finnish - Finland | 
| fo_FO | Faroese - Faroe Islands | 
| fr_BE | French - Belgium | 
| fr_CA | French - Canada | 
| fr_CH | French - Switzerland | 
| fr_FR | French - France | 
| fr_LU | French - Luxembourg | 
| gl_ES | Galician - Spain | 
| gu_IN | Gujarati - India | 
| he_IL | Hebrew - Israel | 
| hi_IN | Hindi - India | 
| hr_HR | Croatian - Croatia | 
| hu_HU | Hungarian - Hungary | 
| id_ID | Indonesian - Indonesia | 
| is_IS | Icelandic - Iceland | 
| it_CH | Italian - Switzerland | 
| it_IT | Italian - Italy | 
| ja_JP | Japanese - Japan | 
| ko_KR | Korean - Republic of Korea | 
| lt_LT | Lithuanian - Lithuania | 
| lv_LV | Latvian - Latvia | 
| mk_MK | Macedonian - North Macedonia | 
| mn_MN | Mongolia - Mongolian | 
| ms_MY | Malay - Malaysia | 
| nb_NO | Norwegian(Bokmål) - Norway | 
| nl_BE | Dutch - Belgium | 
| nl_NL | Dutch - The Netherlands | 
| no_NO | Norwegian - Norway | 
| pl_PL | Polish - Poland | 
| pt_BR | Portugese - Brazil | 
| pt_PT | Portugese - Portugal | 
| rm_CH | Romansh - Switzerland | 
| ro_RO | Romanian - Romania | 
| ru_RU | Russian - Russia | 
| ru_UA | Russian - Ukraine | 
| sk_SK | Slovak - Slovakia | 
| sl_SI | Slovenian - Slovenia | 
| sq_AL | Albanian - Albania | 
| sr_RS | Serbian - Serbia | 
| sv_FI | Swedish - Finland | 
| sv_SE | Swedish - Sweden | 
| ta_IN | Tamil - India | 
| te_IN | Telugu - India | 
| th_TH | Thai - Thailand | 
| tr_TR | Turkish - Turkey | 
| uk_UA | Ukrainian - Ukraine | 
| ur_PK | Urdu - Pakistan | 
| vi_VN | Vietnamese - Vietnam | 
| zh_CN | Chinese - China | 
| zh_HK | Chinese - Hong Kong | 
| zh_TW | Chinese - Taiwan |