In Japanese language, elder brother is "ani". The younger brother is "otohto". Likewise, elder sister is "ane" and the younger sister is "imohto". Japanese language has independent word (also letter) for elder brother, younger brother, elder sister and younger sister. To know this difference at the beginning of learning english is one of the greatest culture shock for japanese. My dictionary says the word elder is a synonym of old used only for the relation of brothers and sisters and so taught in schools. And I hear it rarely used in USA.
How are they doing in other country? The Google Translation Service gives a good tool for knowing it. But it require special fonts be installed for several of the language (japanese is also one of it) . Here I collected the translation of , , , in the following table with the help of Google translation and some other translation sites including InterTran, Free Online Translator, and SYSTRAN.
The resemblance of letters in japanese and chinese is natural. Chinese use two same letters when spoken orally. Chinese letters (kanji) are ideogram and have basically one-syllable pronunciaion in China. Chinese language has four tone of pronunciation for every vowel but it is difficult to distinguish the meaning from one syllable words. This may be the explanation why they use double words in spoken language. Similarly, chinese words are often consisted of two letters of almost the same meaning thus making the meaning clear.
Ainu people are thought to have lived in all over the japanese land in very ancient days. Nowadays they are absorbed modern japanese and pure bloods are thought less than thirty thousands. Their language has apparently distinction about brother and sister and has a peculiar structure.
Korean language does not have the distinction of younger brother and younger sister and they are distinguished adding the word meaning male or female. But I think japanese "otohto" and "imohto" can be separatedinto "oto" (male) and "hto", "imo" (female) and "hto". The structure of Korean and Japanese languages might be of similar stucture.
The southeastern countries can be divided into two groups. The Asian continent group including Korean, Thai, Lao, Vietnamese do not have the distinction of younger brother and younger sister. The island group (though Malaysia is in a peninsula can be thought half island. In jpanese language the word for peninsula is "hantoh" meaning "half island") do not have independent word even for brother and sister.
As to Turkish, the accuracy of the translation is doubtful but it seems it has independent words for elder brother and sister, younger brother and sister.
Seeing European countries, it is evident that they have the same structure though there can be seen English group (English, Dutch, German, Denmark, Norwegian and Sedish), Latin group (Italian, French, Romanian) and Iberaian group (Portuguese, Spanish). Portuguese and Spanish look fairly different in wording but hermano and irmao are not so different in pronunciation and menor of Spanish seems to be the compound of mais novo in Portuguese. Romania is really a Roman country seeing the similarity of the language to Italian. Finnish is a little different as identified as Ural language group in which Estonian and Hungarian can be counted. But as a whole they have all the same structure. As to Russian, the letter „A corresponds to B in english, „‚ to R and „R to S. Thus „q„‚„p„„ correspond Brat and „ƒ„u„ƒ„„„‚„p to Sestra and the similarity to enlish group are distinct.
Finnish is thought a Ural language group together with Estonian and Hungarian and the The word for brother seems not similar to the ones of english group. But the structure is the same.
French and Italian are very similar. Romanian is a Roman country by the name and very similar to Italian. Spanish and Portuguese seem considerably different seeing th wording but I suppose the pronunciations are not so different.
As to Arabic, I am not sure but found at a site or Arabic in Japanese. The words for brother, sister, older and younger are my guess. Probably is the "older" and is the "younger" and the structure is the same as english group.