Hi,
I downloaded an anime with 101 episodes. But there is no mention of subtitle language in the MediaInfo of each episode. Here is a MediaInfo of an episode.
Code:
General
Unique ID                   : 251179150358015544059735320204159656488 (0xBCF7583EC8FC569D6B1C1CBD7426A228)
Complete name               : E:\Arr Downloads\Anime\Slam Dunk (1993)\Season 01\Slam Dunk - S01E01 - The Gifted Basketball Player Is Born!!.mkv
Format                      : Matroska
Format version              : Version 4
File size                   : 340 MiB
Duration                    : 23 min 9 s
Overall bit rate            : 2 053 kb/s
Encoded date                : UTC 2022-07-06 18:46:24
Writing application         : HandBrake 1.4.2 2021100300
Writing library             : Lavf58.76.100
ErrorDetectionType          : Per level 1
Attachments                 : AliciOne Demo.otf / ASSEENONTV_0.ttf / BISONPRR.TTF / blue highway d.ttf / charlie.ttf / Cicle_Gordita.ttf / Comfortaa_Bold.ttf / Constance_0.ttf / coughymachine_0.ttf / Drakoheart Revofit Solid_0.ttf / Exo-Bold.otf / Folks-Normal_0.ttf / Furore.otf / HACKED.ttf / Katanf.ttf / New Athletic M54.ttf / OldNewspaperTypes.ttf / olivier_demo.ttf / Quote_0.ttf / Risque-Regular.otf / SF_Cartoonist_Hand_SC_Bold.ttf / SF_Collegiate_Solid.ttf / Smart_Kid.otf / tf2build.ttf / Times New Romance.ttf / Walkway_Black.ttf / Walkway_UltraBold.ttf

Video
ID                          : 1
Format                      : HEVC
Format/Info                 : High Efficiency Video Coding
Format profile              : Main@L4.1@Main
Codec ID                    : V_MPEGH/ISO/HEVC
Duration                    : 23 min 9 s
Width                       : 1 440 pixels
Height                      : 1 080 pixels
Display aspect ratio        : 4:3
Frame rate mode             : Constant
Frame rate                  : 23.976 (24000/1001) FPS
Color space                 : YUV
Chroma subsampling          : 4:2:0
Bit depth                   : 8 bits
Default                     : Yes
Forced                      : No
Color range                 : Limited
Color primaries             : BT.709
Transfer characteristics    : BT.709
Matrix coefficients         : BT.709

Audio
ID                          : 2
Format                      : AAC LC
Format/Info                 : Advanced Audio Codec Low Complexity
Codec ID                    : A_AAC-2
Duration                    : 23 min 9 s
Channel(s)                  : 2 channels
Channel layout              : L R
Sampling rate               : 48.0 kHz
Frame rate                  : 46.875 FPS (1024 SPF)
Compression mode            : Lossy
Delay relative to video     : -21 ms
Title                       : Stereo
Language                    : Japanese
Default                     : Yes
Forced                      : No

Text
ID                          : 3
Format                      : ASS
Codec ID                    : S_TEXT/ASS
Codec ID/Info               : Advanced Sub Station Alpha
Duration                    : 22 min 30 s
Compression mode            : Lossless
Default                     : No
Forced                      : No

Menu
00:00:00.000                : :Chapter 1
00:11:51.711                : :Chapter 2
00:21:05.264                : :Chapter 3
00:22:36.355                : :Chapter 4
In the TEXT tab, you can see there is no mention of language. I can add the subtitle language name using MKVToolNix but one file at a time. That anime has 101 episodes. So, editing 101 files one by one is very tedious. I couldn't figure out how to edit all the files at once in MKVToolNix.

Please help me with this. Thanks in advance.